JPH08170492A - Excavating device for small bore propulsion device - Google Patents

Abstract

PURPOSE: To improve excavating efficiency and prevent the partial wear of an excavating disc so as to improve the service life of each disc cutter by making a ratio between the inner diameter and outer diameter of the disc cutters the same as a radius ratio from the rotational center to the inside and outside of the disc cutters so as to make the excavating discs of the disc cutters roll without slipping on the working face. CONSTITUTION: In an excavating device rotatably disposed at the tip part of a small bore propulsion device and provided with plural disc cutters at the front face, at least two rows of disc cutters D1 -D3 are disposed radially around a rotary shaft, and a ratio between the inner diameter and outer diameter of all the disc cutters D1 -D3 is made the same as a radius ratio from the rotational center to the inside and outside of the disc cutters D1 -D3 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-diameter propulsion device used for burying a sewer pipe or the like, and more particularly to a rotary excavating device provided at its tip.

[0002]

2. Description of the Related Art In underground burial of a sewer represented by sewer, shield method, propulsion method, etc. are taken into consideration in consideration of recent increase of traffic volume, congested underground burial, and influence on local residents. The so-called non-open cutting method has come into wide use.

Among them, a small-diameter propulsion device has been developed, which is intended especially for those having a diameter of less than 500 mm and which does not require a complicated and large-scale mechanism such as a shield machine.

FIG. 10 is a perspective view showing in simplified form a leading conductor portion of a conventional small-diameter propulsion device. Reference numeral 50 is a leading conductor body, and 51 is an excavator rotatably provided at the tip of the leading conductor body 50. . A tool bit 52 is provided on the front outer edge of the excavation device 51, and a straight type disk cutter 5 is provided in the radial direction.
3, and a pair of tapered disc cutters 54 are provided so as to sandwich the disc cutter 53.

The straight type disc cutter 53 is a plurality of abacus ball-shaped excavating discs having a cutting edge at the tip arranged on the same axis at predetermined intervals, and both ends thereof are rotatable by bearings (not shown). It is supported. By rotating the excavator while pressing the disc cutter 53 toward the face, the disc cutter 5 is rotated.
3 rolls, causing the tip of the drilling disc to bite into the gravel or rock formation.

As a result, a so-called wedge action acts on the ground, and large gravel and rocks are crushed while repeating small surface peeling and surface crushing, and dragging or digging up the gravel of the ground in front of the face as in the past. In addition, the stability of the face is excellent and excavation with a small torque is possible. In addition, since stable excavation is possible, there is little vibration and noise, and it has excellent reliability.

[0007]

However, in the above-mentioned excavating device, the straight type in the radial direction including the center of rotation,
That is, since all the excavating disc cutters have the disc cutters 53 having the same diameter, when the entire device rotates, the excavating discs closer to the center of rotation and the excavating discs closer to the outer periphery of the disc cutters 53 are separated. It is impossible to crush while rotating together, and the excavating disk near the outer periphery rolls while slipping, and a sufficient crushing effect cannot be obtained.

Further, since all the excavating discs have the same diameter, the rotational movement direction and the rotational direction of the excavating discs do not coincide with each other, and the excavating discs cannot bite at right angles to the ground surface. As a result, there is also a problem that the original wedge action of the disc cutter does not act on the inner side of the rotation, and only the inner side of the tip of the excavating disc tends to be worn out.

It is therefore an object of the present invention to improve the excavation efficiency by rotating a plurality of excavation discs without slipping, and reduce uneven wear of the excavation discs to improve the product life.

[0010]

In order to solve the above-mentioned problems, the present invention provides an excavator which is rotatably disposed at the tip of a small-diameter propulsion device and has a plurality of disk cutters on its front surface. The disc cutters are arranged in at least two or more rows in the radial direction around the rotation axis, and the ratio of the inside diameter to the outside diameter of all of these disc cutters is defined as the radius ratio from the center of rotation to the inside and outside of the disc cutter. It is characterized by being the same as.

Here, as the disc cutter, a rod-shaped excavating bit in which an auxiliary cutter is projected between a plurality of discs having a cutting face on the outer peripheral portion, or a tip is fixed to the tip in the radial direction including the center of rotation. A plurality of groups can be arranged.

[0012]

The ratio of the inner diameter to the outer diameter of all the disc cutters arranged in at least two rows in the radial direction around the rotation axis is the same as the radius ratio from the rotation center to the inside and the outside of the disc cutter. As a result, the rolling distance of the outermost excavating disc and the rolling distance of the innermost excavating disc become the same as the distance traveled by the rotation of the excavator for each distance from the center, which causes all the excavating discs to face You will be able to roll while touching the ground without sliding.

Further, since the cutting edges of all the disc cutters act at right angles to the ground surface, uneven wear of the excavating disc is prevented.

Further, by providing the auxiliary cutter between the excavating discs, the residual portion between the excavating discs formed by the crushing of the ground by the excavating discs is further crushed by the auxiliary cutter and the inter-excavating discs are crushed. It becomes possible to advance the crushing without increasing the friction of the valley portion.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The features of the present invention will be specifically described below with reference to the embodiments shown in the drawings. 1 is a front view of an excavator for a small diameter propulsion device according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA of FIG. 1, FIG. 3 is a sectional view taken along the line BB of FIG. Figure 1
FIG. 9 is a sectional view taken along line CC of FIG.

Reference numeral 10 denotes a frame of an excavator having a circular front shape rotatably attached to the tip of a small-diameter propulsion device. Four inner disc cutters D ₁ are located on the innermost side around the rotation axis. The outer disk cutters D ₂ are arranged at 90 ° intervals, and four outer disk cutters D ₂ are also arranged closer to the outer periphery than the inner disk cutter D ₁ . Further, between the inner disc cutters D ₁ and an outer D ₂ provided at 90 degree intervals from each other, the intermediate disc cutter D ₃ are arranged four.

The inner disc cutter D ₁ , the outer disc cutter D ₂ , and the intermediate disc cutter D ₃ are so-called tapered disc cutters, and the four drilling discs 20 have a diameter that increases from the center of rotation to the outside. ing.

Reference numeral 20a designates an auxiliary cutter provided between the four excavating discs 20, which is sharply pointed upward in order to enhance the crushing effect, and the height of which is adjacent to each other. The average height is 1/3.
By setting the height to 1/3 in this way, the opening of the tip of the drilling disk 20 can be ensured as in the conventional case, and it is formed without reducing the discharging effect of the crushed rock. It is possible to effectively crush the remaining portion.

Further, five rod-shaped drill bits 15 having tips 15a fixed to the tip thereof are arranged in the radial direction including the center of rotation of the frame 10, and one drill bit is provided below the middle drill bit 15. 15 are arranged. With such a structure, it becomes possible to efficiently excavate the central portion, which has been difficult to excavate conventionally.

Referring to FIG. 3, the intermediate disc cutter D ₃
Is a pair of pedestals 11 a, 1 fixed to the frame 10.
1b is rotatably supported, and the axis of rotation is inclined in a direction that decreases toward the outside, so that the line connecting the front surfaces of the four excavating disks having different outer diameters is orthogonal to the traveling direction. Further, the receiving bases 11a and 11b are detachably attached to the frame 10 with bolts 12. The inner disk cutter D ₁ has a basic mounting structure similar to that of the intermediate disk cutter D ₃ .

FIG. 4 is a sectional view showing the mounting structure of the outer disc cutter D ₂ , and the inner disc is the above-mentioned intermediate disc cutter D ₃
Similarly, the frame 10 is rotatably supported by a pedestal 13a fixed to the frame 10 by bolts 12, and the outer side is rotatably supported by a pedestal 13b fixed to the side surface of the frame 10 by bolts 14.

Further, referring to FIGS. 5, 6 and 7, the relationship between the ratio of the inner diameter and the outer diameter of the disc cutter and the radius ratio from the center of rotation to the inner and outer sides of the disc cutter will be described in detail. To do. 5 and 6 are explanatory diagrams showing geometrical conditions of the disc cutter, and FIG. 7 is an explanatory diagram showing a rotation state of the disc cutter shown in FIG.

The inner disc cutter D ₁ will be described. In the inner disc cutter D ₁ , the diameter of the innermost excavating disc is d ₁ , the diameter of the outer excavating disc is d ₂ , and the center of rotation 0 to the inner excavating disc. Is the distance or radius r ₁ and the radius to the outer drilling disc is r ₂
Then, r ₂ / r ₁ = d ₂ / d ₁ , that is, the ratio of the inside diameter to the outside diameter is the same as the radius ratio from the center of rotation to the inside and outside of the disk cutter.

Next, the rolling condition of the inner disc cutter D ₁ will be explained. As shown in FIG. 7, the innermost excavating disc diameter d ₁ and the outer excavating disc diameter d ₂ of the inner disc cutter D ₁ are shown. for ratio is the same as the ratio of the radius r ₂ from the center of rotation 0 to a radius r ₁ and outer drilling disk to the inside of the drilling disk, the diameter d
While _{the second} outer drilling disc makes one rotation L ₂ = [pi] d ₂
The inner drilling disc with rolling and diameter d ₁ is L ₁ = π
Since d ₁ rolls, the following expression (1) is established. L ₂ / L ₁ = d ₂ / d ₁ (1)

Here, as shown in FIG. 6, the arc lengths l ₁ and l ₂ when the central angle is θ and the radii are r ₁ and r ₂ , are l ₁ = r ₁ θ and l _{2 respectively.} = R ₂ θ, and l ₁ and l ₂
The ratio of can be expressed by the following equation (2). l ₂ / l ₁ = r ₂ / r ₁ (2) Here, from the condition r ₂ / r ₁ = d ₂ / d ₁ , the formula (2) is expressed as l ₂ / l ₁ = d ₂ / D ₁ (3) Therefore, from the equations (3) and (1), l ₂ / l ₁ = L ₂ / L ₁ (4) That is, the formula (4) is given by the inner disc cutter D
₁ , innermost drilling disc rolling distance and rotation distance,
It also means that the rolling distance and the rotation distance of the outermost excavating disc match, and the inner disc cutter D ₁ rotates both inside and outside without slipping.

Incidentally, this relationship is related to the outer disc cutter D.
₂ and the ratio of the diameters d ₃ and d ₅ of the innermost excavating disc to the diameters d ₄ and d ₆ of the outermost excavating disc and the radius r ₃ from the center of rotation 0 to the inner excavating disc in the intermediate disc cutter D ₃ . , R ₅ and the ratio of the radii r ₄ , r ₆ to the outer drilling disc.

As a result, all disc cutters D _1,
D _2, D ₃ without drilling disc slipping of, it becomes possible to roll a natural ground surface, as shown in FIG. 8 (a), it is possible to enhance the crushing effect exerts a wedge effect. Further, by making all the disc cutters D _1, D _{2 and} D ₃ taper type, as shown in FIG. 8B, the outer surface and the inner surface of the disc cutter uniformly bite into the ground and the outer surface. There is no play at all, which prevents uneven wear of the inner surface of the drilling disc.

FIG. 9 is a detailed view showing the excavation condition.
The remaining portion R ₀ formed between the excavating disks 20, 20 by crushing the rock R further advances, and the tip of the remaining portion R ₀ touches the auxiliary cutter 20 a, so that the auxiliary cutter 2
0a drives the wedge into the remaining portion R ₀ to grow a crack. In this case, the remaining portion R ₀ has a narrow width formed between the drilling disks 20, 20,
The cracks are easily crushed by the growth of the cracks, and the remaining portion R ₀ is crushed from the root. Moreover, the drilling disc 2
Since the width of the tip of 0,20 can be secured as much as that of the conventional one, the drilling disk 20 for crushed rocks,
It is possible to maintain the discharge effect without increasing the clogging between 20.

[0029]

According to the present invention, the following effects can be obtained.

(A) The ratio of the inner diameter to the outer diameter of all of the disk cutters arranged in at least two rows in the radial direction about the rotation axis is the same as the radius ratio from the center of rotation to the inside and outside of the disk cutter. By doing so, all the excavation discs of the disc cutter can roll without slipping on the face, and excavation efficiency is improved.

(B) Since the outer surface and the inner surface hit the ground evenly, the play on the outer surface is eliminated and uneven wear of the excavating disk is prevented, thereby improving the life of the disk cutter.

(C) Providing the auxiliary cutter between the excavating disks enables efficient excavation without causing clogging even in the case of hard rock.

(D) By arranging a plurality of rod-shaped excavating bits having tips fixed to the tip in the radial direction including the center of rotation, it becomes possible to efficiently excavate the central portion, which has been difficult to excavate conventionally. .

[Brief description of drawings]

FIG. 1 is a front view of an excavator for a small diameter propulsion device that is an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

3 is a cross-sectional view taken along the line BB of FIG.

4 is a cross-sectional view taken along the line CC of FIG.

FIG. 5 is an explanatory diagram showing geometric conditions of a disc cutter.

FIG. 6 is an explanatory diagram showing geometric conditions of a disc cutter.

FIG. 7 is an explanatory diagram showing a rotation state of the disc cutter shown in FIG. 1.

FIG. 8 is an explanatory diagram showing a usage situation of the disc cutter shown in FIG. 1.

9 is an explanatory diagram showing a usage situation of the disc cutter shown in FIG. 1. FIG.

FIG. 10 is a perspective view showing a conventional excavator for a small diameter propulsion device.

[Explanation of symbols]

D ₁ inner disc cutter D ₂ outer disc cutter D ₃ intermediate disc cutter 10 frame 11a, 11b, 13a, 13b cradle 12, 14 bolt 15 drill bit 15a tip 20 drill disc 20a auxiliary disc

Claims (3)

[Claims] 1. An excavator which is rotatably arranged at the tip of a small-diameter propulsion device and has a plurality of disk cutters on its front surface, wherein the disk cutters are arranged in at least two rows in a radial direction about a rotation axis. Excavation for a small-caliber propulsion device, characterized in that the ratios of the inner diameter and the outer diameter of all of these disc cutters are the same as the radius ratio from the center of rotation to the inner and outer sides of the disc cutter. apparatus. 2. The excavator for a small-caliber propulsion device according to claim 1, wherein the disc cutter has an auxiliary cutter protruding between a plurality of discs each having a cutting face on the outer peripheral portion thereof. 3. The excavating device for a small-bore propulsion device according to claim 2, wherein a plurality of rod-shaped excavating bits each having a tip fixed to the tip thereof are arranged in a radial direction including a center of rotation.