JP2002097888A - Master and slave shield excavating method and different diameter connecting segment for registing reaction force - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a master and slave shield excavating method capable of easily progressing a slave shield without excessively increasing a hard process, and to provide a segment to be used for the same. SOLUTION: In a master and slave shield excavating method of starting a slave shield 3 from a master shield 1, a different diameter connecting segment 22 for resisting reaction force for connecting a master segment 10 assembled in the master shield 2 and a slave segment 11 to each other is previously formed, and the different diameter connecting segment 22 for resisting reaction force is assembled in a terminal end of the master segment 10 assembled in the master shield 2, and the different diameter connecting segment 22 for resisting reaction force starts the slave shield 3 while receiving the reaction force.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of excavating a parent-child shield for starting a child shield from a parent shield, and a segment assembled with the parent-child shield.

[0002]

2. Description of the Related Art As shown in FIG. 22, when a child shield 54 is started from a parent shield 53, a reaction for receiving a reaction force of the child shield 54 is applied to a parent machine side segment 10 assembled in a pit 55 with the parent shield 53. A force receiving member 50 is provided, and the child shield 54 is started while taking a reaction force with the reaction force receiving member 50.

As shown in FIGS. 23 and 24, the reaction force receiving member 50 is formed of a plate projecting inwardly of the mine to receive the rear end of the slave unit-side segment 11, and the reaction force receiving member 50 A large number of ribs 51 are provided to support the force receiving member 50 from behind.
The reaction force receiving member 50 and the rib 51 are firmly welded to the parent machine side segment 10, respectively, so that the child shield 54 is formed.
To withstand the great forces from

[0004]

However, since the reaction force receiving member 50 and a large number of ribs 51 are welded in a narrow downhole 55, the workability is extremely poor, and the ribs 51 are arranged at a narrow interval.
However, there is a problem in that an additional difficult process in which welding must be performed is required.

[0005] In addition, because the work is difficult on-site,
It is difficult to ensure the surface accuracy of the surface 52 that receives the slave unit-side segment 11, and there is a problem that the slave unit-side segment 11 is brought into close contact and water cannot be stopped well.

After the reaction force receiving member 50 is provided, the child shield must be started by the required space in order to secure a space for tail assembly of the child shield. However, there is a problem that a complicated process is required such that the tail must be restarted after the tail is assembled.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of excavating a parent-child shield capable of easily starting a child shield without increasing the number of difficult steps, and a segment used in the excavation method. is there.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method of excavating a parent-child shield for starting a child shield from a parent shield. A reaction force receiving different diameter connection segment for connection is formed in advance, and a reaction force reception different diameter connection segment is assembled at the final end of the parent machine side segment assembled with the parent shield, and the assembled reaction force reception segment is assembled. A radial connection segment that starts a child shield while taking reaction force. There is no need to weld a reaction force receiving member or the like for receiving the reaction force of the child shield to the parent machine side segment in a narrow mine, and the child shield can be easily started.

Further, the reaction force receiving different-diameter connection segment is carried into the erector, and the reaction force receiving different-diameter connection segment is connected to the final end of the parent machine side segment to assemble a different diameter connection segment ring. After that, in the shield frame of the parent shield, assemble the slave unit side segment to near the jack of the child shield, start the child shield while taking the reaction force with the assembled slave unit side segment, and assemble the child unit side segments sequentially. Good.

Further, the reaction force receiving different diameter connection segment is carried into the erector, and the reaction force receiving different diameter connection segment is connected to the final end of the parent machine side segment to assemble a different diameter connection segment ring. After that, the parent shield is dug further to secure the space for assembling the child shield in front of the different diameter connection segment ring, and the child shield is assembled. It is advisable to start the child shield while taking the reaction force at the child unit side segment.

In the segment structure used when the child shield is started from the parent shield, the outer peripheral portion of the end face at the rear end is connected to the parent machine side segment ring at the final end,
The front end inner peripheral portion may be formed so as to be connected to the slave unit side segment ring to be constructed.

A master end plate connected to the master-side segment ring is provided on the inner periphery of the rear end of the arc-shaped steel plate formed to have the same curvature as that of the master-side segment ring. On the inner circumference, a slave-side end face plate connected to the slave unit side segment ring is provided, the both end face plates are connected by tapered ribs, and connection end face plates are provided at both circumferential ends of the arc-shaped steel plate. Good.

The rib has a hook formed by bending a radially inner portion in a circumferential direction, and the child-side end face plate is used for bolting a segment having the same diameter as the parent machine-side segment. The outer peripheral side bolt holes are formed at substantially equal pitches in the circumferential direction, and the inner peripheral side bolt holes for bolting the slave unit segments are circumferentially spaced from the outer peripheral side bolt holes so as to avoid the hooks. It is good to form at substantially the same pitch.

[0014]

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

As shown in FIGS. 1 and 15, a parent-child shield 1 is provided with a large-diameter parent shield 2 and a concentrically dividable child shield 2 provided in the parent shield 2. It consists of a shield 3.

The parent shield 2 is formed in a thick, substantially cylindrical shape.

The child shield 3 comprises a front trunk 4 and a rear trunk 5 which is provided at the rear end of the front trunk 4 so as to be bendable. Only a part is arranged in the parent shield 2.

The child shield 3 takes in a cutter 6 rotatably provided on the front trunk 4 and located at a front end in the excavation direction, and excavated soil (not shown) in a cutter chamber 7 formed behind the cutter 6. Screw conveyor 9 to send to the back of the mine 8
And an erector 12 for assembling the parent device side segment 10 or the child device side segment 11, and the parent device side segment 1
0 or a shield jack 13 for taking a reaction force from the slave unit side segment 11.

The cutter 6 is a spoke extension jack (not shown) for extending and contracting the cut spoke 14 in the radial direction.
When digging into parent and child together, Katas Spoke 1
4, the outer diameter of the cutter 6 is adjusted to the size of the parent shield 2 and, when excavating only with the child shield 3, the cutter spoke 14 is contracted to reduce the outer diameter of the cutter 6 to the size of the child shield 3. It is designed to match.

The screw conveyor 9 is provided with a front end opened in the lower part of the cutter chamber 7 and inclined so as to raise a rear end side. At the rear end of the screw conveyor 9, there is provided a screw gate 15 for opening and closing the earth and sand conveying passage.

The erector 12 includes a swivel ring 16 provided on the front trunk 4 of the child shield 3 via a frame member (not shown) or the like, and a master unit side segment 10 or a slave unit side segment provided on the swivel ring 16. And an assembly arm 17 for gripping and moving the assembly 11 to a predetermined assembly position.

The assembling arm 17 is formed so as to be expandable and contractible. By changing the amount of expansion and contraction, not only the master unit side segment 10 but also the slave unit side segment 11 can be assembled.

The shield jack 13 is provided integrally with the rear trunk 5 of the child shield 3. When excavating together with the parent and child, an adapter 18 is provided at the tip for contacting the front end of the parent machine side segment 10. Adapter 18 to parent shield 2
The guide 20 provided on the parent shield frame 19 guides the child shield 1 so as to be able to expand and contract in the longitudinal direction.

A reaction force receiving knock pin 2 for fixing the parent shield 2 and the child shield 3 to each other in the axial direction is provided.
A plurality of members 1 are inserted and fixed in the radial direction, so that a force received from the front surface of the cutter 6 is integrally received by the parent and the child.

When the child shield 3 is started from the parent shield 2, the parent machine side segment 1 assembled with the parent shield 2 is used.
At the end of 0, a factory (not shown) equipped with processing equipment in advance
Reaction-force receiving different-diameter connection segment 22 formed of
a, 22b and 22c are assembled.

As shown in FIGS. 1 and 3, the reaction force receiving different diameter connection segments 22a, 22b, 22c are used to connect the master unit side segment 10 assembled with the master shield 2 to the slave unit side segment 11. A normal type segment 22a whose both end surfaces in the circumferential direction extend in the radial direction; a key type segment 22b formed in a C shape so that both end surfaces in the circumferential direction face the outer peripheral side; and a normal type segment 22a. And a connection type segment 22c positioned between the key type segment 22b and the connection type segment 22c to connect them together (hereinafter, the segment assembled into a ring shape is referred to as a segment ring).

As shown in FIG. 2, each type of the reaction force receiving different diameter connection segments 22a, 22b, 22c.
Is formed such that the outer peripheral portion 38 at the rear end face is connected to the parent device side segment ring 23 at the final end, and the inner peripheral portion 39 at the front end is connected to the slave unit side segment ring 26 to be constructed. .

More specifically, FIG. 1 and FIGS.
As shown in FIG.
Reference numerals 22b and 22c denote master unit side segment rings 2 respectively.
Arc-shaped steel plates 24a, 24 formed to have the same curvature as the curvature of FIG.
4b, 24c, a master unit side segment ring 2
3 are provided on the inner surfaces of the arc-shaped steel plates 24a, 24b, and 24c.
Child-side end face plate 27 connected to child-unit-side segment ring 26
a, 27b, 27c are provided, and the both end face plates 25, 27 are connected by a plurality of tapered ribs 28a, 28b, 28c. The connection end plates 29 and 30 for connecting the different diameter connection segments 22 are provided.

The parent end plates 25a, 25b, 25c are formed so that the inner peripheral end and the outer peripheral end are aligned with the main unit side segment 10, so that the main unit side segment 1 has no irregularities.
0.

The child-side end plates 27a, 27b, and 27c have outer ends formed with the same curvature as the parent end plates 25a, 25b, and 25c. It is formed so as to match the peripheral end, and is formed to extend radially inward from the parent end face plates 25a, 25b, 25c.

The child-side end plates 27a, 27b, 27c
The outer peripheral side bolt hole 43 for bolting the special segment 34 having substantially the same shape as the parent machine side segment 10 is provided.
And an inner peripheral bolt hole 44 for bolting the slave unit side segment 11 are formed.

The outer peripheral side bolt hole 43 is formed in the child side end face plate 27.
A, 27b, and 27c are formed on the outer peripheral side so as to have a substantially equal pitch in the circumferential direction.

The inner peripheral side bolt hole 44 is formed in the child side end face plate 27.
On the inner peripheral side of a, 27b, and 27c, it is formed so as to be substantially equidistant from the outer peripheral side bolt hole 43 in the circumferential direction so as to avoid the hook portion. Thus, the inner peripheral side bolt hole 44 can be formed at a position displaced in the circumferential direction from the hook portion 42, and can be easily bolted without being hidden behind the hook portion 42 (outer peripheral side). ing.

As shown in FIG. 2, the ribs 28a, 28b,
Reference numeral 28c denotes a plate thickness such that the proof force is within the allowable stress even if an eccentric load equivalent to the eccentric amount e of the outer diameter difference between the master unit side segment ring 23 and the slave unit side segment ring 26 is applied. And the shape has been determined. And specifically,
Each of the ribs 28a, 28b, 28c has a hook 42 formed by bending a radially inner end in the circumferential direction, and is formed in an L-shaped cross section.

Each type of reaction force receiving different diameter connection segments 22a, 22b, 22c is provided with a grout socket 31 for injecting a backfill material and a hoist (not shown). Is provided.

The segments 10, 11, 22a, 22b,
The connection between the end plates 22c is such that the end plates are overlapped and bolted together.

The manufacturing of the reaction force receiving different diameter connection segment 22 is performed in a factory equipped with processing equipment, so that a product having sufficient processing accuracy can be easily manufactured.

Assembling of the reaction force receiving different diameter connection segment 22 is performed by using the erector 12 in the same manner as the ordinary parent machine side segment 10. Therefore, there is no need to weld a member (not shown) for receiving the reaction force to the parent machine side segment 10 in the narrow downhole 8, and it is possible to omit a difficult and time-consuming process.

As shown in FIG. 15, after assembling the different diameter connection segment rings 33, in order to secure a space for assembling the child shield 3 in the parent shield 2, the parent shield 2 is further excavated while being dug. In the parent shield frame 19, a special segment 34 having substantially the same shape as the parent machine side segment 10 is assembled.

Then, as shown in FIG. 16, after the special segment 34 is fixed to the parent tail frame 35 of the parent shield 2 by welding, the shield jack 13 is retracted, and the adapter 18 is removed from the tip of the shield jack 13. Thereby, a sufficient work space for assembling the child shield 3 in the parent tail frame 35 can be secured.

Thereafter, in order to further facilitate the operation, the screw gate 15 protruding into the parent tail frame 35 is removed, and as shown in FIG. (Not shown), the blind lid 36 is installed.

Then, as shown in FIG. 2, a waterproof seal 40 made of a backfill material is provided on the inner peripheral side of the special segment 34.

As shown in FIGS. 16 and 17, the child tail frame 37 of the child shield 3 is transported into the pit 8, and is assembled to the child shield 3 using the erector 12 or a chain block (not shown). As shown in (1), the slave unit side segment 11 is assembled to the vicinity of the shield jack 13.

At this time, the inner peripheral bolt hole 44 is
Since it is formed so as to be displaced in the circumferential direction from 2, the bolt can be easily tightened without being hidden behind the hook portion 42.

Then, the blind cover 36 is removed, the screw gate 15 is attached again, and a backfill material is injected from a child tail frame 37 of the child shield 3 and a grout hole (not shown) provided in the child device side segment 11. Te parent shield 2
The gap between the child shield 3 and the shield jack 1
3, the front thrust is transferred from the parent shield frame 19 of the parent shield 2 to the child device side segment 11.

As shown in FIG.
And the outer diameter of the cutter 6 is adjusted to the child shield 3,
Pull out the reaction force receiving knock pin 21. The child shield 3 is completely separated from the parent shield 2 and is ready to start.

Thereafter, as shown in FIG. 20, the child shield 3
, The sub-unit-side segments 11 are sequentially assembled.

Propulsion is obtained by extending the shield jack 13.

When the shield jack 13 is extended, the force is transmitted to the reaction force receiving different-diameter connection segments 22a, 22b, 22c via the slave unit-side segment 11, and the reaction force reception different-diameter connection segments 22a, 22b, 22c. It is transmitted to the parent machine side segment 10 assembled further behind 22c.
Since the parent machine side segment 10 does not move, the child shield 3 is propelled.

As described above, the reaction force receiving segments 22a, 22b, 22a, 22b, for connecting the master unit side segment 10 and the slave unit side segment 11 assembled by the master shield 2 are connected.
22c are formed in advance, and reaction force receiving different diameter connection segments 22a, 22b, 22c are assembled at the final end of the parent machine side segment 10 assembled by the parent shield 2, and the assembled reaction force receiving different diameter connection is assembled. Segments 22a, 22
In b and 22c, the child shield 3 is started while taking a reaction force, so that it is possible to eliminate the difficult and high-accuracy welding work performed in the underground 8 where the work is narrow and has poor workability. Can be reduced, the surface accuracy of the connection surface with the slave unit-side segment 11 can be easily secured, and the water can be stopped well.

Also, the reaction force receiving different diameter connection segment 22
a, 22b, and 22c are connected to the final end of the parent machine side segment 10 by the
After assembling the slave unit 3, the slave unit-side segment 11 is assembled in the parent shield frame 19 of the parent shield 2 to the vicinity of the jack 13 of the child shield 3, and the assembled child unit segment 11 takes a reaction force to obtain the child shield. 3 and the child device side segments 11 are sequentially assembled, so that the child shield 3 can be easily started from the parent shield 2.

Further, the reaction force receiving different diameter connection segments 22a, 22b and 22c are connected to the final end of the parent machine side segment 10 by the erector 12 to assemble the different diameter connection segment ring 33, and then the different diameter connection segment is formed. Ring 33
In order to secure a space for assembling the child shield ahead of the parent shield 2, the parent shield 2 is further dug by two to three rings of the parent machine side segment 10, and the child shield 3 is assembled.
The child unit side segment 11 is assembled to the vicinity of the jack 13, and the child shield 3 is started while taking a reaction force by the assembled child unit side segment 11, so that the assembly space of the child shield 2 can be easily secured. ,
The child shield 2 can be quickly and easily started.

The rear end end outer peripheral portion 38 is connected to the final end master unit side segment ring 23, and the front end end surface inner peripheral portion 39 is connected to the slave unit side segment ring 26 to be constructed. Connection segments 22a, 22
b, 22c are formed, so that the normal base unit side segment 1
The structure for receiving the slave unit-side segment 11 can be easily provided in the mine 8 simply by assembling it in the mine 8 using the erector 12 as in the case of FIG.

Also, arcuate steel plates 24a, 24b, 24c formed to have the same curvature as that of the parent machine side segment ring 23.
On the inner periphery of the rear end, there are provided parent end face plates 25a, 25b, 25c connected to the parent machine side segment ring 23, and on the inner peripheral end of the arc-shaped steel plates 24a, 24b, 24c, the child machine side segment ring 26 and Child-side end plates 27a, 27b, 2 to be connected
7c, the two end face plates 25, 27 are connected by tapered ribs 28a, 28b, 28c, and connection end face plates 29, 30 are provided at both circumferential ends of the arc-shaped steel plates 24a, 24b, 24c. Connecting segment 22 for receiving reaction force
a, 22b, 22c, the reaction force receiving different-diameter connection segments 22a, 22b, 22c can be easily controlled in attitude by the erector 12, and the downhole 8 can be controlled with the same simplicity as the ordinary base unit side segment 10. Can be assembled.

The ribs 28a, 28b, 28c are
A hook portion 42 is formed by bending the inner side in the radial direction in the circumferential direction. An outer peripheral side for bolting a special segment 34 having the same diameter as that of the parent machine side segment 10 is provided on the child side end face plates 27a, 27b, 27c. The bolt holes 43 are formed at substantially the same pitch in the circumferential direction, and the inner peripheral bolt holes 44 for bolting the slave unit-side segments 11 are formed from the outer peripheral bolt holes 43 so as to avoid the hooks 42. Since it is formed so as to be shifted at a substantially equal pitch in the direction, it is possible to secure a work space for bolt tightening while forming the reaction force receiving different diameter connection segments 22a, 22b, 22c with sufficient strength. , Reaction force receiving different diameter connection segments 22a, 22
b, 22c, special segment 34 and slave unit side segment 1
1 can be easily connected.

In the embodiment, the reaction force receiving different-diameter connection segment 22 having a tapered shape in a side view is described. However, the present invention is not limited to this. For example, as shown in FIG. The reaction force receiving different diameter connection segment 41 may be used.

[0057]

In summary, according to the present invention, the following excellent effects can be obtained.

(1) The child shield can be easily started without increasing the number of difficult steps.

(2) Water can be satisfactorily stopped between the slave unit side segment and the master unit side segment.

[Brief description of the drawings]

FIG. 1 is a side view of a parent-child shield and a segment showing a preferred embodiment of the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a sectional view taken along line III-III in FIG.

FIG. 4 is a plan view of a child shield starting segment.

FIG. 5 is a view taken along line VV of FIG. 4;

FIG. 6 is a view taken along line VI-VI of FIG. 4;

FIG. 7 is a view taken along line VII-VII of FIG. 4;

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

FIG. 9 is a plan view of a child shield starting segment.

FIG. 10 is a view taken along line XX of FIG. 9;

FIG. 11 is a view taken along line XI-XI in FIG. 9;

FIG. 12 is a plan view of a child shield starting segment.

FIG. 13 is a view taken along line XIII-XIII in FIG. 12;

FIG. 14 is a view taken along line XIV-XIV of FIG.

FIG. 15 is a side view of the parent-child shield in preparation for starting the child shield.

FIG. 16 is a side view of the parent-child shield in preparation for starting the child shield.

FIG. 17 is a side view of the parent-child shield in preparation for starting the child shield.

FIG. 18 is a side view of the parent-child shield in preparation for starting the child shield.

FIG. 19 is a side view of the parent-child shield in preparation for starting the child shield.

FIG. 20 is a side view of the parent-child shield during child-child launch.

FIG. 21 is a side view of a parent-child shield and a segment showing another embodiment.

FIG. 22 is a schematic explanatory view of a conventional method.

FIG. 23 is an enlarged view of a main part of FIG. 22;

FIG. 24 is a perspective view of FIG. 23.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Parent-child shield 2 Parent shield 3 Child shield 10 Parent machine side segment 11 Child machine side segment 12 Elector 13 Shield jack (jack) 19 Parent shield frame 22a Reaction force receiving different diameter connection segment 22b Reaction force reception different diameter connection segment 22c Reaction Force Receiving Different Diameter Connection Segment 23 Base Unit Side Segment Ring 24a Circular Steel Plate 24b Circular Steel Plate 24c Circular Steel Plate 25a Main Side End Plate 25b Main Side End Plate 25c Main Side End Plate 26 Child Unit Side Segment Ring 27a child-side end face plate 27b child-side end face plate 27c child-side end face plate 28a rib 28b rib 28c rib 29 connection end face plate 30 connection end face plate 33 different diameter connection segment ring 38 end face outer peripheral part 39 end face inner peripheral part 42 hook part 42 43 Outer bolt hole 44 Inner bolt hole

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Mitsuo Kunichika, Inventor 4-11, Yuyookacho, Tennoji-ku, Osaka, Osaka Prefecture Inside Morimoto Gumi Co., Ltd. (72) Takashi Horinaka 4, Yuyuokacho, Tennoji-ku, Osaka, Osaka No. 11 Morimoto Gumi Co., Ltd. (72) Inventor Joru Yoshida 11-1, Kitahama-cho, Chita-shi, Aichi Prefecture Ishikawajima-Harima Heavy Industries Co., Ltd.Aichi Factory (72) Inventor Shigeo Fujii 11-1, Kitahama-cho, Chita-shi, Aichi Prefecture Ishikawajima Harima Heavy Industries, Ltd. Aichi factory F-term (reference) 2D054 AA03 AC02 AD07 BA03 DA03 EA09 2D055 BA01 BB01 EB01

Claims (6)

[Claims] In a method of excavating a parent-child shield for starting a child shield from a parent shield, a reaction force receiving different-diameter connection segment for connecting a parent-unit-side segment and a child-unit-side segment assembled with the parent shield is formed in advance. Then, a reaction force receiving different diameter connection segment is assembled at the last end of the parent machine side segment assembled with the parent shield, and the child shield is started while taking a reaction force with the assembled reaction force receiving different diameter connection segment. A method of excavating a parent-child shield, characterized in that: 2. The reaction force receiving different-diameter connection segment is carried into the erector, and the reaction force receiving different-diameter connection segment is connected to the final end of the parent machine side segment to assemble a different diameter connection segment ring. After that, in the shield frame of the parent shield, assemble the slave unit side segment to near the jack of the child shield, start the child shield while taking the reaction force with the assembled slave unit side segment, and assemble the child unit side segments sequentially. The method for digging a parent-child shield according to claim 1. 3. The reaction force receiving different diameter connection segment is carried into the erector, and the reaction force reception different diameter connection segment is connected to the final end of the parent machine side segment to assemble a different diameter connection segment ring. After that, the parent shield is dug further to secure the space for child shield assembly in front of the different diameter connection segment ring, and after assembling the child shield,
The method for excavating a parent-child shield according to claim 1 or 2, wherein the child device-side segment is assembled near the jack of the child shield, and the child shield is started while taking a reaction force with the assembled child device-side segment. 4. A segment structure used for starting a child shield from a parent shield, wherein an outer peripheral portion of an end surface at a rear end is connected to a parent machine side segment ring at a final end, and an inner peripheral portion of an end surface at a front end is formed by a child to be constructed. A reaction force receiving different diameter connection segment formed so as to be connected to a machine side segment ring. 5. A main end plate connected to the main unit side segment ring is provided on the inner periphery of the rear end of the arcuate steel plate formed to have the same curvature as that of the main unit side segment ring. On the inner circumference, a slave side end face plate connected to the slave unit side segment ring is provided, and the both end face plates are connected with a tapered rib,
5. The different diameter connection segment for receiving a reaction force according to claim 4, further comprising connection end plates provided at both ends in the circumferential direction of the arc-shaped steel plate. 6. The rib has a hook formed by bending a radially inner portion in a circumferential direction, and the child-side end face plate is used for bolting a segment having the same diameter as the parent machine-side segment. The outer peripheral side bolt holes are formed at substantially equal pitches in the circumferential direction, and the inner peripheral side bolt holes for bolting the slave unit segments are circumferentially spaced from the outer peripheral side bolt holes so as to avoid the hooks. The reaction force receiving different diameter connection segment according to claim 5, wherein the connection segments are formed at substantially equal pitches.