JP3334926B2 - Multiple shield excavator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multiple shield excavator for constructing a tunnel having an overlapping circular cross section in which a plurality of circles partially overlap.

[0002]

2. Description of the Related Art As one of multiple shield excavators, a plurality of spoke-type rotary cutters are arranged such that the center-to-center distance is larger than any of the rotary cutters adjacent to each other and smaller than the sum of both the rotary radii. Arrange on almost the same plane as there is,
Japanese Patent Application Laid-Open No. 57-19 / 1979 discloses a method of obtaining an overlapping circular excavation section formed by the outer peripheral edge of the rotation locus of each rotary cutter.
7395 and the like.

[0003] In addition, a branchable multiple shield excavation suitable for continuously constructing a multiple shield tunnel having an overlapping circular cross-sectional shape and one or more single circular shield tunnels branched therefrom. And Japanese Patent Application No. 2-234471 (Japanese Patent Application Laid-Open No. 4-1150).
96) has been proposed by the present applicant. This multi-branch shield excavator that can be branched has multiple cylindrical parts in parallel,
And a multiple shield body having an overlapping circular cross-sectional shape that is connected so as to partially overlap, and the multiple shield so as to have a concentric relationship with some of the plurality of cylindrical portions. A single circular shield body stored within the shield body,
A cutter head for excavating a front face of each of the shield bodies, wherein the cutter head includes a first cutter head supported by the multiple shield body and a second cutter head supported by the single circular shield body. It consists of a cutter head.

[0004]

In the former multiple shield excavator, as shown in FIG. 13, two rotary cutters 83 and 83 'which are disposed adjacent to each other on substantially the same plane are respectively provided on the front surface. Equipped with the same number of spokes 88, 88 'to which a number of bits 89, 89' are attached, they are rotationally driven at the same speed in opposite directions with a predetermined phase difference so that the cutters do not interfere with each other.

[0005] However, this configuration is based on the premise that the excavation diameter and excavation extension of the adjacent rotary cutters 83 and 83 'are equal. The number of bits of each rotary cutter and the selection range of bit burden are narrow, and it is difficult to provide bit equipment corresponding to the excavation diameter and extension of excavation.

For example, when two rotating cutters having different excavation diameters are arranged adjacent to each other on substantially the same plane to excavate a tunnel having an overlapping circular cross section having different diameters as shown in FIG. If the number of spokes and the rotation speed of the adjacent rotary cutters are the same according to the conventional example of the above, the rotary cutter with the larger excavation diameter cannot be equipped with the number of bits corresponding to the excavation diameter (the amount of excavated soil). As a result, the bit load becomes excessive and the number of bit replacements during construction is increased.On the other hand, with a rotary cutter with a small excavation diameter, the bit load is light, but the peripheral speed of the outer peripheral part is low, so the excavation The effect of stirring is not sufficiently obtained, and this tendency becomes more remarkable as the difference between the excavation diameters of the two rotary cutters is larger.

[0007] In the latter multi-branch shield excavator capable of branching, when the first and second cutter heads are arranged in the same plane, which is desirable for stable face, both cutter heads are rotated with the same number of spokes and the same rotation speed. Assuming that the cutter is a cutter, the rotating cutter supported by the multiple shield body has a relatively short excavation extension, so the number of bits provided is somewhat excessive. Since the rotary cutter supported by the circular shield body has a long excavation extension, the number of bits provided tends to be insufficient, and it is necessary to replace worn bits during excavation, which is not economical in manufacturing and constructing a shield machine. For this reason, in Japanese Patent Application No. 2-234471, as shown in FIG.
The first cutter head 94 supported by the multiple shield main body 91 only the cutter heads 95 and 96
As a rocking excavation type cutter that rocks within a range that does not interfere with the second cutter heads 95 and 96, bit equipment and bit load distribution corresponding to the excavation extension of each cutter head are intended. If the cutter head 94 is an oscillating excavation type cutter, an area where the second cutter heads 95 and 96 do not reach the excavation area and the excavation and agitation action is generated, and it is difficult to uniformly excavate the excavated earth and sand. .

The present invention has been made in view of the above points, and has as its object to provide a plurality of rotary cutters which are arranged substantially on the same plane in order to obtain an overlapping circular excavation section. It is an object of the present invention to provide a multiple shield excavator which can be equipped with a bit corresponding to the excavation diameter or excavation extension and which can simultaneously excavate the entire face and uniformly agitate excavated soil by a plurality of rotary cutters.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a plurality of spoke-type rotary cutters are arranged so that a plurality of spoke-shaped rotary cutters can be cut by any of the excavating radii of the rotary cutters having adjacent centers. Multiple shields that are arranged on substantially the same plane so as to be smaller than the sum of both excavation radii, and to obtain an overlapping circular excavation section formed by the outer peripheral edge of the rotation trajectory of each rotary cutter In the excavator, the adjacent rotary cutters are provided as rotary cutters having different numbers of spokes, and a cutter driving device for rotating both rotary cutters in opposite directions at a speed ratio inversely proportional to the ratio of the number of spokes is provided. It is characterized by. Further, according to claim 2
The invention according to claim 1, wherein a plurality of sports
Rotation in which a rotary cutter is supported by one shield body
Number of spokes in adjacent rotating cutters
The rotating cutter with the larger number is the one with the smaller number of spokes
It is characterized in that the excavation diameter is larger than the cutter. Ma
The invention described in claim 3 is the same as the invention described in claim 1.
In addition, the number of spokes in the adjacent rotary cutter is small
The rotating cutter has a plurality of cylindrical parts arranged in parallel and
Multi-layers with overlapping circular cross-sections
Rotation of the one with more spokes supported by the continuous shield body
The cutter is provided for a part of the plurality of cylindrical portions.
In the multiple shield body so that they are concentric.
Supported by a separable single circular shield body received
It is characterized by being. The invention according to claim 4
The invention according to claim 1, wherein the plurality of spoke-shaped
Rotating cutter with rotating cutter supported by one shield body
And the number of spokes in the adjacent rotary cutter is large.
The other rotating cutter has the smaller number of spokes.
It is characterized in that the excavation diameter is smaller than the diameter. further,
The invention described in claim 5 is the invention according to claim 4.
The rotating cutter with the larger number of spokes is
The excavation diameter is smaller than the rotating cutter with the smaller number of peaks
It is characterized by the following.

[0010]

In the above construction, adjacent rotary cutters having different numbers of spokes arranged on substantially the same plane maintain a speed ratio inversely proportional to the ratio of the number of spokes so that the gears rotate while meshing. It rotates in the opposite direction to each other, and the rotation performs simultaneous excavation of the front face and agitation of excavated earth and sand.

In the case where a plurality of rotary cutters are supported by one shield main body and the excavation diameters of adjacent rotary cutters are different, the number of spokes of the rotary cutter having a larger excavation diameter is increased. , Reduce the rotating speed, reduce the number of spokes of the rotating cutter with the smaller excavation diameter, and increase the rotating speed. By doing so, it is possible to provide a bit corresponding to the drilling diameter of each rotary cutter, and to reduce the difference in peripheral speed between adjacent rotary cutters having different drilling diameters, thereby equalizing the bit load and stirring effect. Can be achieved.

In the multiple shield excavator capable of branching, the rotary cutter having the smaller number of spokes in the adjacent rotary cutter is supported by the multiple shield body having an overlapping circular cross section, and the rotary cutter having the larger number of spokes is supported. By supporting the cutter on a single circular shield body stored in the multiple shield body, it is possible to provide a bit corresponding to the extension of the excavation of each rotating cutter, and to use the rotating cutter with the smaller number of spokes as the number of spokes. By rotating the rotary cutter faster than the rotary cutter having the larger number, each rotary cutter can have an equal stirring effect.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

The first embodiment shown in FIGS. 1 to 5 corresponds to claim 2. As shown in FIG. 1, the multiple shield excavator according to the present embodiment includes two spoke -type rotary cutters 2 and 3 having different excavation diameters, which are arranged adjacently on substantially the same plane. . The rotary cutter 2 having a larger excavation diameter has six spokes 4 each having a large number of bits 5 attached to a front surface thereof, and a center bit 6 provided at a tip portion.

Further, the rotary cutter 3 having a smaller excavation diameter is used.
Has a large number of bits 8 each attached to the front
It has a spoke 7 and is provided with a center bit 9 at the tip. These rotary cutters 2 and 3 are individually driven by a cutter driving device described later, and rotate at a speed ratio (1: 2 in this example) inversely proportional to the ratio of the number of spokes without mutual interference in opposite directions. In this case, since the rotary cutter 2 has an excavation diameter nearly twice as large as the rotary cutter 3, the speed ratio between the rotary cutter 2 and the rotary cutter 3 is set to 1:
If it is set to 2, the difference between the outer peripheral portion peripheral speeds becomes smaller than the case where the speed ratio is 1: 1.

In FIG. 2 to FIG. 4, reference numeral 1 denotes a shield main body, as shown in FIG. The rotary cutters 2 and 3 are supported by bearings (not shown) on a partition wall 10 that partitions the cutting face into a face side and an inside of the machine. The multiple shield excavator according to the present embodiment is an earth pressure shield, in which a face is excavated by two rotary cutters 2 and 3, excavated earth and sand are spokes 4 and 7, and a stirring blade 11 provided on the back of these spokes. , 12 into the cutter chamber 13 formed between each of the rotary cutters 2 and 3 and the partition wall 10 and knead with the mud material injected from an injection port (not shown) to form mud having plastic fluidity. After the conversion, it is configured to be discharged backward by the screw conveyor 14. In FIG. 4, reference numeral 15 denotes a cutter drive motor, which transmits torque from the plurality of cutter drive motors 15 to the respective rotary cutters 2 and 3 via a speed reducer 16, a pinion 17, a gear 18, and a center shaft 19. Along with the excavation, the segment 20 is assembled at the tail portion of the shield main body 1 to have the same shape as the shield cross section, and the assembled segment 20 is used as a reaction force receiving member for the shield jack 2.
1 propels the shield body 1. FIG. 5 shows an assembled shape of the segment 20.

According to this embodiment, two rotary cutters 2 and 3 having different excavation diameters can be equipped with bits 5 and 8 and stirring blades 11 and 12 of a number corresponding to each excavation diameter. As described above, the difference between the peripheral speeds of the outer peripheral portions of the two rotary cutters 2 and 3 is reduced so that the bit load can be equalized. Further, for the rotating cutter 3 having a small number of spokes, the stirring speed is supplemented by increasing the rotation speed, thereby enabling uniform stirring of the excavated earth and sand.

In this embodiment, two rotary cutters are used.
The present invention can also be applied to a multiple shield excavator in which three or more rotary cutters having different excavation diameters of adjacent rotary cutters are supported by one shield body. Further, the present embodiment is a horizontal multiple shield excavator, but can be applied to a vertical multiple shield excavator in which a plurality of rotary cutters are arranged in parallel in the vertical direction.

The second embodiment shown in FIGS.
It corresponds to. As shown in FIG. 6, the multiple shield machine according to this embodiment includes three spoke-type rotary cutters 25, 26, and 27 that are arranged adjacent to each other on substantially the same plane.

7 and 8, reference numeral 22 denotes a multiple shield body having an overlapping circular cross-sectional shape formed by connecting three cylindrical portions 22a, 22b, 22c in parallel and partially overlapping. , 24 are the three cylindrical portions 22a, 2
The multiple shield main body 2 is arranged so as to be concentric with the left and right two cylindrical portions 22b and 22c among the two shield portions 2b and 22c.
A separable single circular shield body housed in 2,
The central rotary cutter 25 among the three rotary cutters 25, 26, 27 is provided on a partition wall 28 provided in the central cylindrical portion 22 a of the multiple shield main body 22, and the left and right rotary cutters 26, 27 are provided with a single left and right circular shape. It is supported by partition walls 29 and 30 provided on the shield main bodies 23 and 24 via bearings (not shown). The center rotary cutter 25 has four spokes 31 each having a large number of bits 32 attached to the front surface, and a center bit 33 is provided at the tip.
The left and right rotating cutters 26 and 27 have eight spokes 34 and 35 respectively having a large number of bits 36 and 37 attached to the front surface thereof.
39 are provided. Neighboring rotary cutters 25 and 26
Are individually driven by a cutter driving device described later, and rotate at a speed ratio (2: 1 in this example) inversely proportional to the ratio of the number of spokes without mutual interference in opposite directions. The same applies to the adjacent rotary cutters 25 and 27. The multiple shield excavator of the present embodiment is also an earth pressure shield, in which a face is excavated by three rotating cutters 25, 26, and 27, and excavated earth and sand are provided on spokes 31, 34, and 35 and on the back of these spokes. The rotary cutters 25, 26, 27 and the partition walls 28,
Cutter chamber 43, 4 formed between 29, 30
4, 45, and is mixed with the mud material injected from an injection port (not shown) to convert it into mud having plastic fluidity, and then discharged backward by a screw conveyor (not shown).

When this multiple shield excavator is used for construction of a subway station tunnel and a tunnel between stations, a single circular shield main body 23, 24 is stored in the multiple shield main body 22 in the planned section of the station tunnel. In this state, the rotary cutters 25, 26, and 27 supported by the respective shield bodies are simultaneously operated to excavate the face, and the overlapping circular segment 46 is assembled at the tail portion of the multiple shield body 22. The shield jacks 47 and 48 serve as the reaction force receiving members,
By propelling 23 and 24, as shown in FIG. 9, a space 49 for the central station building and spaces 50 and 5 for the rails on both sides are provided.
The station tunnel consisting of 1 is formed at once by three overlapping circular shield tunnels. After the excavation of the station section scheduled section, the welded portion 52 that fixed the single circular shield main bodies 23 and 24 to the multiple shield main body 22 is cut off, and the rear support portions 53 and 54 of the single circular shield main bodies 23 and 24 are separated. Are transferred to the front supports 55, 56, and a single circular segment is connected to the existing overlapping circular segment 46 in the tail space formed at the trace jacks 47, 48. Thereafter, the rotating cutters 26 and 27 supported by the single circular shield bodies 23 and 24 are operated, and each of the single circular shield bodies 23 and 24 is independently propelled, so that the extension of the excavation route can be performed. Start branch excavation to build a shield tunnel with a single circular cross section that will be a tunnel between stations. At this time, if the center rotary cutter 25 is fixed at a position that does not interfere with the rotary cutters 26 and 27 (a position where the spoke 31 is inclined at about 45 degrees), it does not become an obstacle to branch excavation. FIG. 10 shows a state immediately after the start of branch excavation. 57 and 58 are single circular segments laid horizontally at the time of branch excavation. The two-dot chain lines 23 'and 24' indicate the positions when the single circular shield bodies 23 and 24 were stored in the multiple shield main body 22, and the two-dot chain lines 26 'and 27' indicate the rotation at this time. Cutter 2
6 and 27 are shown.

In this multiple shield excavator, the center rotary cutter 25 is used only for excavation of the station tunnel, and the left and right rotary cutters 26 and 27 used for excavation of both the station tunnel and the inter-station tunnel. Excavation length is shorter than that. Therefore, as shown in FIG. 6, by reducing the number of spokes of the center rotary cutter 25 and increasing the number of spokes of the left and right rotary cutters 26 and 27, a bit device corresponding to the extension of each rotary cutter can be provided. This makes it possible to increase the economical efficiency in the production and construction of the shield machine, and also makes the right and left rotary cutters 2
By increasing the rotation speed by the smaller number of spokes than in 6, 27, the stirring ability is supplemented, and uniform stirring of excavated soil can be achieved.

In this embodiment, there are two single circular shield bodies housed in the multiple shield body, but the number of housed can be changed as appropriate.

Next, adjacently arranged on substantially the same plane,
A cutter driving device for rotating rotating cutters having different numbers of spokes without interfering with each other will be described.

The cutter driving device 60 shown in FIG. 11 has almost the same configuration as the cutter synchronous operating device of the multiple shield excavator proposed by the present applicant as Japanese Patent Application No. 1-260300 (Japanese Patent Application Laid-Open No. 3-125794). ing.

This figure shows the motor groups 15-1, 15-2, 1
5-3 is a rotary cutter 2 via reduction gears 16-1, 16-2, 16-3 and pinions 17-1, 17-2, 17-3.
And the motor groups 15-4, 15-5, 15-6 are connected to the speed reducers 16-4, 16-5, 16-6, and the pinion 17-.
It shows that it is connected to the rotary cutter 3 via 4, 17-5 and 17-6. A three-phase squirrel-cage induction motor (IM) is used as a cutter drive motor for each group, and two rotary cutters 2, 3 having different numbers of spokes are electrically controlled at a predetermined speed ratio (for example, 1: 2). They are rotated without mutual interference.

In order to rotate the two rotary cutters at different speeds, there are a method in which the rotational speeds of the motors are different, and a method in which the reduction ratios of the speed reducers are different. Are set to the same speed, and the speed reducers 16-1, 1
6-2, 16-3 and 16-4, 16-5, 16-6 are made different in reduction ratio.

The speed control unit 61-1 for the motor groups 15-1, 15-2, and 15-3 converts the AC output of the speed generator (TG) 64-1 directly connected to the motor 15-1 into F- ■ conversion. Device 65-1 converts it into a DC signal proportional to the rotation speed,
A speed controller (AS) corresponding to a deviation between this signal (speed detection value) and a speed command (speed setting value) from the speed setting device 63
R) The output of 66-1 is output to motor groups 15-1, 15-2, 1
A torque command (torque current set value) for 5-3 is given to each of the torque control units 62-1, 62-2, and 62-3. On the other hand, the speed controller 61-2 for the motor groups 15-4, 15-5, and 15-6 converts the AC output of the speed generator (TG) 64-2 directly connected to the motor 15-4 into an F- ■ converter. At 65-2, the signal is converted into a DC signal proportional to the rotation speed,
This signal (speed detection value) is the sum of the speed command (speed setting value) from the speed setting device 63 and the deviation angle signal (deviation angle detection value) of the synchronizing device including the synchro transmitter 67 and the synchro control transformer 68. And outputs the output of the speed controller (ASR) 66-2 corresponding to the deviation to the motor groups 15-4,
Each of the torque control units 62-4, 62-5, as torque commands (torque current set values) for 15-5 and 15-6.
62-6.

In this case, since the rotation speeds of the rotary cutter 2 and the rotary cutter 3 are different, the axis of the rotary cutter 2 (L axis) and the synchro-transmitter 27, the axis of the rotary cutter 3 (R axis) and the synchro control transformer Transmission gears 67 for respectively connecting the motors 68
a, 68a by changing the ratio of the number of teeth to match the rotation speeds of the synchro transmitter 67 and the synchro control transformer 68,
The synchro-control transformer 68 outputs a voltage having a magnitude and a polarity corresponding to a deviation angle from a predetermined phase difference between the two output axes a and 68a as a deviation angle signal.

The torque control units 62-1 to 62-6 are all composed of the same components, and FIG. 11 shows a schematic configuration as representatives of 62-1 and 62-4. The torque control unit 62-1 will be described. The vector calculation unit 70-1 performs vector synthesis based on the torque current set value given from the speed controller 66-1 and the magnetizing current value given from the magnetic flux setter 69-1. The converted equivalent two-phase current value is subjected to two-phase to three-phase conversion to obtain a primary current set value. Then, the deviation between the primary current set value and the primary current detection value obtained by the current detector 71-1 is input to a current controller (ACR) 72-1.
The output of 2-1 is supplied to the inverter 75-1 as a pulse width control signal by the PWM modulator 73-1. The motor 15-1 is supplied to the motor 15-1 to control the torque of the motor 15-1. Similarly, the torque control units 62-2 and 62-3 control the torque of the motors 15-2 and 15-3 according to the torque command from the speed controller 66-1, and the torque control units 62-4 and 62-3.
5, 62-6 controls the torque of the motors 15-4, 15-5, 15-6 in accordance with the torque command from the speed controller 66-2. As a result, the motor groups 15-1, 15-2, 1
The generated torque of 5-3 is controlled such that the deviation between the detected speed value and the set speed value becomes zero, and the motor groups 15-4, 15-
The generated torques 5, 15-6 are controlled so that the deviation between the detected speed value and the set speed value and the deviation angle from a predetermined phase difference between the two output-side shafts of the transmission gears 67a, 68a are both zero. For details of torque control, refer to Japanese Patent Application No. 1-203030.
0, the description is omitted.

FIG. 12 is a diagram for explaining mutual interference between the two cutters when the number of spokes of the rotary cutter 2 is eight and the number of spokes of the rotary cutter 3 is four as an example. Is shown. From this position, when one of the rotary cutters 2 is fixed and the other rotary cutter 3 is rotated counterclockwise, and the rotation angle of the rotary cutter 3 until the rotary cutter 2 hits the rotary cutter 2 is represented by θ. An allowable deviation angle between the two output-side shafts of the transmission gears 67a and 68a shown in FIG.
The motor groups 15-4 and 15- described above so that the deviation angle from the predetermined phase difference between the two axes is kept within this allowable deviation angle.
By performing the torque control of 5, 15-6, both cutters can be rotated without mutual interference.

In a multiple shield excavator having three or more rotating cutters as shown in FIG. 6, a cutter driving device having the same configuration as that of FIG. Can be.

[0033]

According to the present invention, the rotary cutters arranged adjacent to each other on substantially the same plane of the multiple shield excavator are formed as rotary cutters having different numbers of spokes, so that adjacent rotary cutters are excavated. If the diameter or excavation length is different, each rotary cutter can be equipped with a bit corresponding to the excavation diameter or excavation extension, which reduces the cost of manufacturing shield machines and the cost of replacing bits during construction. Effect is obtained.

Further, by providing a cutter driving device for rotating the adjacent rotary cutters in directions opposite to each other at a speed inversely proportional to the ratio of the number of spokes, a difference in the number of spokes arranged adjacently on substantially the same plane is provided. The front cutter can be simultaneously excavated by the rotating cutter, and the rotating cutter with the smaller number of spokes is increased in rotational speed to supplement the stirring capacity, and the excavated soil is uniformly stirred by each rotating cutter. As a result, the face can be stabilized and the soil can be smoothly discharged.

[Brief description of the drawings]

FIG. 1 is a front view showing a cutter arrangement according to a first embodiment of the present invention.

FIG. 2 is a horizontal sectional view of the multiple shield machine according to the first embodiment.

FIG. 3 is a sectional view taken along line III-III of FIG. 2;

FIG. 4 is a vertical sectional view of the multiple shield machine according to the first embodiment.

FIG. 5 is a diagram showing a segment assembly shape of the multiple shield machine according to the first embodiment.

FIG. 6 is a front view showing a cutter arrangement according to a second embodiment of the present invention.

FIG. 7 is a horizontal sectional view of a multiple shield machine according to a second embodiment.

8 is a sectional view taken along line VIII-VIII of FIG.

FIG. 9 is a diagram illustrating a segment assembly shape of the multiple shield machine according to the second embodiment.

FIG. 10 is a plan view showing a state immediately after the start of branch excavation of the multiple shield excavator according to the second embodiment.

FIG. 11 is a schematic diagram of a cutter driving device according to the first embodiment.

FIG. 12 is an explanatory diagram of mutual interference between rotating cutters having different numbers of spokes.

FIG. 13 is a front view of a conventional example of a multiple shield machine.

FIG. 14 is a front view of another conventional example of a multiple shield machine.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Shield body, 2, 3 ... Rotary cutter, 4, 7 ... Spoke, 5, 8 ... Bit, 22 ... Multiple shield body, 22
a, 22b, 22c ... cylindrical part, 23, 24 ... single circular shield body, 25, 26, 27 ... rotary cutter, 31,
34, 35 ... spokes, 32, 36, 37 ... bits, 6
0: cutter driving device.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-286095 (JP, A) JP-A-57-197395 (JP, A) JP-A-3-125794 (JP, A) JP-A-2- 285196 (JP, A) JP-A-2-285197 (JP, A) JP-A-2-18594 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) E21D 9/08 E21D 9 / 06 301

Claims (5)

(57) [Claims] 1. A plurality of spoke-type rotary cutters are arranged on substantially the same plane so that the center-to-center distance is larger than any of the excavating radii of adjacent rotary cutters and smaller than the sum of both excavating radii. In a multiple shield excavator in which an overlapping circular excavation section formed by the outer peripheral edge of the rotation trajectory of each rotary cutter is formed, the adjacent rotary cutters are set as rotary cutters having different numbers of spokes, and both rotary cutters are rotated. A multiple shield excavator comprising a cutter driving device for rotating cutters in opposite directions at a speed ratio inversely proportional to the ratio of the number of spokes. 2. A rotary cutter in which a plurality of spoke-type rotary cutters are supported by a single shield main body, and a rotary cutter having a larger number of spokes among adjacent rotary cutters is:
The multiple shield excavator according to claim 1, wherein the excavation diameter is larger than that of the rotary cutter having the smaller number of spokes. 3. A rotary cutter having a smaller number of spokes in adjacent rotary cutters has a multiple circular section formed by connecting a plurality of cylindrical portions in parallel and partially overlapping. The rotating cutter supported by the shield body and having a larger number of spokes is housed in the multiple shield body so as to be concentric with some of the plurality of cylindrical portions. The multiple shield machine according to claim 1, supported on a possible single circular shield body. 4. A plurality of spoke-shaped rotary cutters are provided in one shell.
Rotating cutters supported by the
The rotating cutter with the larger number of spokes in the rotating cutter,
The drilling diameter is smaller than the rotating cutter with the smaller number of spokes.
2. The multiple shield excavation according to claim 1, wherein:
Machine. 5. The rotary cutter having a larger number of spokes.
Excavates more than the rotary cutter with the smaller number of spokes
The multiple seat according to claim 4, wherein the diameter is small.
Ludo excavator.