JP2002339692A - Ground excavator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent sediment from accumulating between cutter bits. SOLUTION: A cutter head 3 has a center bit 20, four first to fourth spoke parts 22a to 22d, the first to eighth cutter bits 24-1 to 24-8 of eight in total, and a ring member 26. The first to eighth cutter bits 24-1 to 24-8 are arranged in order at the same pitch interval P1 along the shaft directional rear side of a boring machine body. Prescribed clearance Δ is arranged between the adjacent first to eighth cutter bits 24-1 and 24-8. The first to eighth cutter bits 24-1 to 24-8 are arranged at the same pitch interval in the radial outside direction from the center of the cutter head 3. First to eighth protective bits 30-1 to 30-8 are arranged so as to be positioned in a root part between the first to eighth cutter bits 24-1 to 24-8.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ground excavator such as a shield excavator.

[0002]

2. Description of the Related Art A shield construction method is known as a construction method employed in construction work of an underground tunnel in an urban area or its suburbs. In this kind of construction method, a shield excavator is used for excavating the ground.

The shield machine excavates the ground by rotating a cutter head rotatably provided at the tip,
A cutter bit for excavating earth and sand is arranged on the cutter head.

[0004] The cutter bit of the shield machine is worn due to excavation of earth and sand, and needs to be replaced in order to extend the excavable distance in the shield machine. In response to such a problem, a shield excavator capable of excavating a long distance by recently enabling excavation of a step-like vertical section has been developed.

FIG. 5 shows the main part. The ground excavator A shown in FIG. 1 includes an excavator main body B and a cutter head C rotatably provided at a front end of the excavator main body B. A leading excavation part D is provided at the center of the tip of the cutter head B.

The cutter head C has a preceding excavation part D
And a plurality of cutter bits E which are sequentially installed at predetermined intervals along the rear side of the excavator body B in the axial direction.

The plurality of cutter bits E are sequentially arranged at predetermined intervals along a radially outward direction from the center side of the cutter head C, and a stepwise vertical cross section excavation from the center to the outside is performed. It constitutes a group of possible step-shaped bits.

However, a cutter bit having such a configuration is used.
The shield machine having E has the technical problems described below.

[0009]

That is, in the cutter bit E of the shield machine shown in FIG. 5, since the leg of each bit E is long and relatively protrudes forward, the cutter bit E is provided between the cutter bits E. The problem is that the excavated soil tends to accumulate and the excavated sediment accumulates between the cutter bits E, so that the sediment pressure in this portion increases, and as a result, the cutter head C is worn or an extra load is applied to the cutter bits E. was there.

The present invention has been made in view of such a conventional problem, and an object of the present invention is to prevent the excavated earth and sand from stagnating between cutter bits, thereby improving the cutter head. An object of the present invention is to provide a ground excavator capable of avoiding wear and an extra load applied to a cutter bit.

[0011]

In order to achieve the above object, the present invention relates to a ground excavator for excavating a ground by rotating a cutter head rotatably provided at a tip thereof. A leading excavation part provided at the center of the tip, and sequentially arranged at a predetermined interval from the preceding excavation part along the rear side in the axial direction of the ground excavator, and has a diameter from the center side of the cutter head. Along the outward direction,
A plurality of cutter bits which are sequentially arranged at predetermined intervals and are capable of excavating in a stepwise vertical cross section from the center outward, and a protection bit is provided at a root portion between the cutter bits.

According to the ground excavator thus configured,
Since the protection bit is provided at the base between the cutter bits, the earth and sand accumulated between the cutter bits can be cut and removed by the protection bit.

When the earth and sand accumulated between the cutter bits is removed, wear of the cutter head and an extra load applied to the cutter bits can be eliminated.

The ground excavator can be suitably used for a shield machine.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIGS. 1 to 4 show a first embodiment of a ground excavator according to the present invention. The embodiments shown in these figures illustrate a case where the present invention is applied to a shield machine.

The shield machine shown in FIG. 1 includes a hollow cylindrical machine 1. The excavator body 1 has a front trunk 1a and a rear trunk 1b, and these front and rear trunks 1a and 1b are provided.
Are foldably connected via a center folding mechanism 11 to be described later.

A cutter head 3 is rotatably provided on the front end side of the front trunk 1a, and a partition wall 2 separating the excavation chamber P is provided on the rear side of the cutter head 3 with a front end side of the front trunk 1a. It is fixed on the inner circumference.

On the back side of the partition 2, a cutter driving device 4 for rotating the cutter head 3, for example, an electric or hydraulic motor, and a power transmission mechanism 5 for transmitting the rotational driving force of the cutter driving device 4 to the cutter head 3. Is provided.

The bulkhead 2 is provided with a screw discharging device 6 constituted by a screw conveyor for carrying the excavated earth and sand taken into the excavating chamber P to the rear side of the machine 1 so as to pass therethrough. Installed.

Further, in the rear trunk 1b, an assembling erector device 9 for the segments S, which is sequentially assembled in a ring shape at the rear side, is installed along with the excavation of the shield excavator.

The cutter head 3 is rotatably supported by the partition wall 2 via a center shaft 10 provided at the center on the back side of the cutter head 3. The center shaft 10 has a portion protruding rearward from the partition wall 2. The power transmission mechanism 5 is connected.

The folding mechanism 11 disposed between the front trunk 1a and the rear trunk 1b includes a sliding part 11a and a seal member 11b, and has a substantially spherical outer periphery at the front end of the rear trunk 1b. A sliding portion 11a is provided, and a rear end of the front body 1a can slide and move therewith.

The seal member 11b covers the outer periphery of these sliding contact portions to prevent infiltration of earth and sand or groundwater.
Between the front trunk 1a and the rear trunk 1b, a plurality of middle folding jacks 14 are provided together with the middle folding mechanism 11.

The center folding jack 14 has a telescopic end connected to the front trunk 1a via a bracket 12 and a fixed end attached to the ring gutter 13 via a bracket 13a.

The center bending jack 14 is appropriately operated when the shield machine is excavated in a curved line or when the direction of the excavation is corrected, so that the front body 1a is bent with respect to the rear body 1b to change the angle between them. This changes the direction of excavation.

The member denoted by reference numeral 13b in FIG.
A bracket extending from the ring gutter 13 in a direction different from that of the bracket 13a, and a shield jack 15 is attached to the bracket 13b.

A plurality of the shield jacks 15 are provided along the circumferential direction of the excavator body 1 and are used when the shield excavator is excavated by taking a reaction force on the segments S assembled in a ring shape.

A tail seal portion 8 having a plurality of tail packings 8a is provided at the rear end of the rear trunk 1b, and the tail packing 8a is brought into sliding contact with the segment S to thereby seal the excavator body 1. To prevent sediment and groundwater from entering the cabin.

The basic structure of the shield machine described above is the same as that of a conventional apparatus of this type, but the shield machine of the present embodiment has a remarkable feature in the cutter head 3.

FIG. 2 is a detailed front view of the cutter head 3 of the present embodiment. The cutter head 3 shown in this figure has a center bit (preceding excavation part) 20, four first to fourth spoke parts 22a to 22d, and a total of eight first to eighth cutter bits 24-1 to 24-1. 24-8 and a ring member 26.

The center bit 20 is installed so as to project from the front surface of a boss 10a fixed to the front end of the center shaft 10 arranged in the center of the cutter head 3 in the digging direction.
By driving the cutter head 3 to rotate, the shield excavator is excavated in a cylindrical shape having a diameter corresponding to its length on the central axis in the excavation direction.

The first to fourth spoke portions 22a to 22d are
It is formed in a cylindrical shape having a predetermined width and length, and radially extends outward from the outer peripheral edge of the boss 10a of the center shaft 10. In the case of the present embodiment, four first to Four spoke portions 22a to 22d are arranged at equal angular intervals of 90 °.

Each of the first to fourth spoke portions 22a-2
2d is the first to fourth as shown in FIG.
The center axis O of the spoke portions 22a to 22d is
Is inclined toward the rear side so as to intersect with the center in the axial direction at a predetermined angle θ.

First to eighth cutter bits 24-1 to 24-
8 are projectingly provided on the front end side of the first to fourth spoke portions 22a to 22d, each of which has a relatively long leg portion 24a.
And a cutter blade 24b provided at the tip of the leg 24a.

In the case of the present embodiment, a total of eight first to eighth cutter bits 24-1 to 24-8 are respectively arranged in one spoke portion 22a to 22d.

That is, the first spoke portion 22a has the first
The fifth cutter bits 24-1 and 24-5 are arranged, and the second
The second and sixth cutter bits 24-2,
24-6 are arranged, third and seventh cutter bits 24-3 and 24-7 are arranged in the third spoke portion 22c, and fourth and eighth cutter bits 24-4 and 2 are arranged in the fourth spoke portion 22d.
4-8 are arranged.

Eight first to eighth cutter bits 24-1 to 24-1
1 to 3 and 4, the first cutter bit 2 extends from the center bit 20 along the rear side in the axial direction of the excavator main body 1 at the same pitch interval P1 from the center bit 20.
The cutter bits are set in the order of 4-1 to the eighth cutter bit 24-8.

Adjacent first to eighth cutter bits 24-1
A predetermined gap Δ is provided between 24-8. In addition, eight first to eighth cutter bits 24-1 to 24-8.
As shown in FIG. 2, from the center of the cutter head 3, the first cutter bit 24-1 to the eighth cutter bit 24-8 are installed in the radial direction at the same pitch interval P1 from the center. And the eighth cutter bit 24-8 is located on the outermost circumference side of these cutter groups.

The ring member 26 is fixed to each of the first to fourth spoke portions 22a to 22d so as to connect between the outer peripheral edges of the first and fourth spoke portions 22a to 22d. Four cutter bits 28 that partially overlap -8 are provided. The cutter bit 28 is arranged at an intermediate position between the four spoke portions 22a to 22d.

Further, in the case of the present embodiment, the first to eighth
A total of eight first to eighth protection bits 30-1 to 30-8 are located at the root between the cutter bits 24-1 to 24-8.
30-8 are provided.

In this embodiment, the first to eighth protection bits 30-1 to 30-8 are the first to eighth cutter bits 24.
Projections are provided on the lower surface sides of -1 to 24-8 and on the front surfaces of the first to fourth spoke portions 22a to 22d.

According to the cutter head 3 configured as described above, when this is rotationally driven by the cutter driving device 4,
As shown in FIG. 3, the center in the axial direction is excavated by the center bit 20, and the outer side thereof is sequentially excavated by the first to eighth cutter bits 24-1 to 24-8.
A face with a step-like vertical excavation cross section extending radially outward from the center is formed.

In this excavation process, a gap Δ is provided between the first to eighth cutter bits 24-1 to 24-8, and this portion is partially enlarged in FIG. Thus, the cutter blade 24b of the cutter bits 24-1 to 24-8
Can not be drilled directly.

The first to eighth cutter bits 24-1 to 24-1
24-8 has a relatively long leg 24a,
As shown in FIG. 4, unexcavated or excavated soil tends to accumulate between the first to eighth cutter bits 24-1 to 24-8, and when sediment accumulates in this portion, the sediment pressure increases, Problems such as wear as described above occur.

However, in the case of the present embodiment, the first to eighth protection bits 30-1 to 30-8 are provided corresponding to the positions where the earth and sand easily accumulate.

Therefore, the cutter bits 24-1 to 24-8
The earth and sand accumulated between the first to eighth protection bits 30-1 to 30 due to the rotation of the cutter head 3 and the forward movement of the excavator body 1.
The cutting can be removed by 30-8.

When the sediment accumulated between the cutter bits 24-1 to 24-8 is removed in this way, the cutter head
The wear on the front side of the first to fourth spoke portions 22a to 22d and the extra load applied to the cutter bits 24-1 to 24-8 can be eliminated.

In the above embodiment, the case where the present invention is applied to a shield excavator which excavates by rotating the cutter head 3 provided at the front end of the excavator main body 1 has been described.
The embodiment of the present invention is not limited to this, and can be applied to a ground excavator that excavates a horizontal hole such as a push pipe shield, a small-mouth propulsion machine, and a TBM.

[0049]

As described above in detail, according to the ground excavator according to the present invention, the excavated soil is prevented from stagnating between the cutter bits, so that the wear of the cutter head and the extra amount of the cutter bits are reduced. Load can be avoided.

[Brief description of the drawings]

FIG. 1 is an explanatory side view showing an overall structure of a shield machine to which a ground excavator according to the present invention is applied.

FIG. 2 is a front view as viewed from a direction A in FIG. 1;

FIG. 3 is an explanatory view of a main part of a cutter head of the shield machine shown in FIG. 1;

FIG. 4 is an enlarged view of a portion B in FIG. 3;

FIG. 5 is an explanatory diagram of a shield machine in which the problem of the present invention exists.

[Explanation of symbols]

Reference Signs List 1 excavator main body 3 cutter head 20 center bit 22a to 22d first to fourth spoke portions 24-1 to 24-8 first to eighth cutter bits 24a legs 24b cutter blade 26 ring member 28-1 to 28-8 1st to 8th protection bits

Continued on the front page (72) Inventor Yoichi Moriya 2-152-2 Konan, Minato-ku, Tokyo Main office of Obayashi Gumi Co., Ltd. (72) Inventor Kenji Murayama 2-15-2 Konan, Minato-ku, Tokyo Main office of Obayashi Gumi Co., Ltd. ) Inventor Kiyoshi Tsuchiya 650, Kandamachi, Tsuchiura-shi, Ibaraki Pref. In the Tsuchiura Plant of Hitachi Construction Machinery Co., Ltd. (72) Inventor Masakazu Fukai 650, Kantachi-cho, Tsuchiura-shi, Ibaraki Pref. 2D054 BA03 BB04 CA09

Claims (2)

[Claims] 1. A ground excavator for excavating a ground by rotating a cutter head rotatably provided at a tip thereof, comprising: a preceding excavation portion provided at a center of a tip of the cutter head; Along the rear side of the ground excavator in the axial direction, they are sequentially installed at a predetermined interval, and, along the radial direction from the center side of the cutter head, are sequentially arranged at a predetermined interval. And a plurality of cutter bits capable of excavating in a stepwise vertical cross section from the center outward, wherein a protection bit is provided at a root portion between the cutter bits. 2. The ground excavator according to claim 1, wherein the ground excavator is a shield machine.