JPH08135845A - Excavation propulsion method using small diameter pipe and excavation bit for excavation propelling machine using small diameter pipe - Google Patents

Abstract

PURPOSE: To perform excavation without reducing propulsion force even if encountering a bituminous layer by theoretically determining the length of the slant face of the blade of a roller bit which rotates on its axis while revolving together with the cutter face of a guide body comprising outer and inner casings and the distance between an excavation face and the open port of a discharge guide hole. CONSTITUTION: The guide body 1 of an excavation propelling machine using a small diameter pipe comprises outer and inner casings 2 and 3 and is provided with roller bits 10 and fixed bits 11 in cutter faces 7 and 8 at the front ends of an outer casing 2a and inner casing 3a in the front section. In this case, under the condition that θis a constant, and an integral range is limited within 0 second and Δt seconds, the distance D between the open port of a discharge guide hole and an excavation face is given both of the equations are compatible, i.e., length L is determined by e+a 1-cos(kωΔt}, and D=(1/2).960.(Δt)<2> . Where, (e), (ω) and (a) represent the length of the slant face of the blade of the roller bit in its radial direction, the revolution angle of the roller bits and radius of the roller bit respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-diameter pipe excavation propulsion method for burial work in which a small-diameter pipe excavator is used to form an excavation hole in the ground and to embed the small-diameter pipe in the excavating hole. The present invention relates to an excavation bit for a small-diameter pipe excavation propulsion machine used in this small-diameter pipe excavation propulsion method. More specifically, consider the positional relationship between the leading conductor that digs into the ground to lead the upper or sewage pipe to be buried, the leading end surface of the hole formed by excavation, and the discharge guiding hole provided in the leading conductor. The present invention relates to a small-diameter pipe excavation propulsion method when performing excavation work, and an excavation bit for a small-diameter pipe excavation propulsion machine used in the small-diameter pipe excavation propulsion method.

[0002]

2. Description of the Related Art Small diameter pipes such as water and sewer pipes, distribution line pipes, communication line pipes and gas pipes are buried in the soil.
A small-diameter pipe excavator is used for such burial work. The small-diameter pipe excavation propulsion machine includes a leading conductor that guides a subsequent small-diameter pipe to be buried and advances while forming a burial hole. A roller bit is rotatably attached to a rotating cutter face provided at the front end of such a leading conductor.

The object to be excavated by such a roller bit is guided to a discharge guide hole having an intake port opened at the front end portion of the leading conductor, and is discharged by a tubular casing forming the leading conductor. It is passed through the road and discharged backward. When this kind of work was being performed using a conventional small-diameter pipe excavator, the excavation capacity of the small-diameter pipe excavator encountered in the gravel layer fell sharply and it became impossible to proceed.

Then, when a vertical hole reaching the tip of the drilling hole is dug and the tip of the drilling hole is examined, it is crushed by the roller bit and is rotated while being sandwiched between two blades of the roller bit. The crushed particles, which should have been discharged by being guided to the discharge guide hole by the roller bit, remained in the lower part of the deepest part of the drill hole. From this, it is considered that the crushed particles crushed by the roller bit slipped on the slope between the two blades of the roller bit and were slid down before being guided to the discharge guide hole.

[0005]

The present invention has been made based on the above technical background, and achieves the following objects.

Another object of the present invention is to provide a small-diameter pipe excavation propulsion method in which the excavation propulsion force does not decrease even if a gravel layer is encountered.

Another object of the present invention is to provide an excavating bit for a small diameter pipe excavating propulsion machine in which crushed particles do not slide down between the blades of the roller bit before being guided to the discharge guide hole.

Another object of the present invention is to provide a drill bit for a small diameter pipe drilling propulsion machine which can be easily designed so that the drilling propulsive force does not decrease even if a gravel layer is encountered.

[0009]

The present invention adopts the following means in order to achieve the above object.

In the small-diameter pipe excavation propulsion method of the present invention, the front conductor (1) consisting of the outer casing (2) and the inner casing (3) is joined to the outer casing (2) and the inner casing (3). The cutter face (8) at the front end of the front conductor (1) and the cutter face (8) so as to freely rotate while revolving with the cutter face (8).
A small diameter of a plurality of sets of roller bits (10) provided on the cutter and a discharge guide hole (16) provided on the cutter face and having an open front end for discharging excavated material excavated by the roller bits. A small-diameter pipe excavation propulsion method using a pipe excavation propulsion device, wherein Δt is obtained by the following equation in which θ is a constant and an integration range is from 0 second to Δt seconds.

[0011]

S = e / cos (α) α: Half of the wedge angle of the roller bit, e: Radial length of the slope of the blade of the roller bit ω: Revolution angular velocity of the roller bit θ: Angle coordinate of the roller bit r: Revolution radius of the roller bit a: Radius of the roller bit k: r / a μ: Coefficient of friction between excavated rock and slope of the roller bit g: Gravitational acceleration β: { kω · (time as a design constant from a reference time point) + 2nπ} (that is, revolution rotation angle position coordinate as a design constant of the roller bit) n: the following equation using an integer L = e + a {1-cos (kωΔt) } For the length L defined by

[0012]

It is characterized in that the excavation is performed by providing a distance D between the discharge guide hole (16) and the excavation surface being excavated so as to have a relationship defined by the following equation.

Further, the excavating bit of the small diameter pipe excavating propulsion machine of the present invention comprises a front conductor (1) comprising an outer casing (2) and an inner casing (3), the outer casing (2) and the inner casing ( Leading conductor (1) connecting 3)
Of a small-diameter pipe excavator, which comprises a cutter face (8) at the front end portion of and a discharge guide hole (16) provided at the cutter face for discharging excavated objects and having an open front end. The excavating bit is a roller bit (10) in which a plurality of sets are provided on the cutter face (8) so as to rotate while revolving with the cutter face (8), and θ is a constant, and the integration range is from 0 second. Δt obtained by the following equation up to Δt seconds

[0014]

S = e / cos (α) α: Half of the wedge angle of the roller bit, e: Radial length of the inclined surface of the blade portion of the roller bit ω: Revolution angular velocity of the roller bit θ: The above Roller bit angular coordinates r: Revolution radius of the roller bit a: Radius of the roller bit k: r / a μ: Coefficient of friction between excavated rock and slope of the roller bit g: Gravitational acceleration β: {kω・ (Time as a design constant from the reference time point) + 2nπ} (that is, revolution rotation angle position coordinate as a design constant of the roller bit) n: The following equation using an integer L = e + a {1-cos (kωΔt)} For the length L defined by

[0015]

It is characterized in that the maximum value e obtained from the equation (12) is designed as the length in the radial direction of the inclined surface of the blade portion of the roller bit.

Further, the excavating bit of the small diameter pipe excavating propulsion machine of the present invention comprises a front conductor (1) comprising an outer casing (2) and an inner casing (3), the outer casing (2) and the inner casing ( Leading conductor (1) connecting 3)
Of the cutter face (8) at the front end and a discharge guide hole (16) provided at the cutter face for discharging the excavated material excavated by the roller bit (10) and having an open front end. A digging bit for a caliber pipe digging propulsion machine, wherein the digging bit is a roller bit (1) provided with a plurality of sets on the cutter face (8) so as to be rotatable while revolving with the cutter face (8).
0), and the front end opening of the discharge guide hole (16) is positioned so as to coincide with or substantially coincide with the front end surface of the cutter face (8), and the roller bit (10).
The length in the radial direction of the blade slope of the roller bit (1
It is characterized by being designed to be smaller than the distance between the cutting edges of 0).

[0017]

In the small-diameter pipe excavation propulsion method of the present invention, the opening of the front end of the discharge guide hole is positioned at a position retracted from the excavation surface which is the front end surface of the excavation hole by an appropriate distance. The crushed crushed particles rotate along with the roller bit while sliding on the slope of the blade edge of the roller bit. The crushed particles that start to fall from the inclined surface of the blade edge portion of the roller bit at a position determined as a design constant while rotating are guided to the discharge guide hole.

The small-diameter pipe excavation propulsion machine of the present invention is
The radial length of the blade slope portion of the roller bit is defined in relation to the position defined as a design constant. The crushed particles that start to fall from the inclined surface of the blade edge portion of the roller bit at a position determined as a design constant while rotating are guided to the discharge guide hole.

Further, the small diameter pipe excavation propulsion machine of the present invention is
It is designed so that the front end opening of the discharge guide hole matches or almost coincides with the front end surface of the cutter face, and the radial length of the beveled part of the roller bit is designed to be smaller than the distance between the cutting edges of the roller bit. Therefore, the front end face of the cutter face is designed to be located within the distance from the excavated surface to the drop point where the crushed particles fall.

[0020]

【Example】

(Embodiment 1) Next, an embodiment of the present invention will be described. FIG.
1 is a front sectional view showing a first embodiment of a small diameter pipe excavation propulsion machine of the present invention. The leading conductor 1 of the small-diameter pipe excavator shown in FIG. 1 digs to the left in the figure. Subsequent to the leading conductor 1 that is being dug, a water pipe is buried in a drill hole formed behind the leading conductor 1. The front conductor 1 includes an outer casing 2 and an inner casing 3.
It consists of and.

The outer casing 2 is composed of a front outer casing 2a and a rear outer casing 2b. The front outer casing 2a and the rear outer casing 2b are bendable by spherical contact between the convex spherical surface portion of the rear end portion of the front outer casing 2a and the concave spherical surface portion of the front end portion of the rear outer casing 2b. Are connected. For this reason, the axis of the front outer casing 2a is set to the rear outer casing 2b.
It can be oriented in any direction within a certain solid angle with respect to the axis.

The inner casing 3 is composed of a front inner casing 3a and a rear inner casing 3b. The outer peripheral surface of the rear end portion of the front inner casing 3a is formed to have a hexagonal cross section as a whole, and a partial convex spherical surface is formed on the top line portion thereof. The inner peripheral surface of the front end portion of the front inner casing 3a is formed to have a hexagonal cross section as a whole, and a partial concave spherical surface is formed on the top line portion thereof.

Therefore, the front outer casing 3a and the rear outer casing 3b are the front outer casing 3a.
The partial convex spherical surface of the rear end portion and the partial concave spherical surface portion of the front end portion of the rear outer casing 3b are spherically connected to each other so that they can be folded inwardly, and the axis of the front inner casing 3a is the rear inner casing. Although it can be oriented in any direction within a certain solid angle range with respect to the axis of 3b, the front inner casing 3a and the rear inner casing 3b are constrained in the rotational direction about the axis and are integrated. Can be rotated. Such a universal joint structure capable of integral rotation is described in detail in Japanese Patent Application No. 4-360744. The angle control between the shaft of the front outer casing 2a and the shaft of the rear outer casing 2b is performed by the fluid pressure cylinder device 9.

A spiral blade 4 is wound around and fixed to each of the cylindrical outer peripheral surfaces of the front inner casing 3a and the rear inner casing 3b. The inner casing 3 and the spiral blade 4 form an auger. A guide hole excavating casing 5 is inserted inside the cylindrical inner peripheral surface of the inner casing 3. A leading hole excavating bit 6 is provided at the front end portion of the leading hole excavating casing 5. The outer casing 2 does not rotate, but the inner casing 3 and the guide hole excavating casing 5 are independently driven to rotate.

A cutter face 7 is rotatably connected to the front end of the front outer casing 2a. The cutter face 7 and the front inner casing 3a of the inner casing 3 are integrally connected by a cutter face 8. The cutter face 8 is provided with a roller bit 10 and a fixed bit 11. 2 and 3 show a cutter face 8 and a roller bit 1 integrally connected thereto.
0, the positional relationship with the outer circumference gauge cutter 11 is shown in detail. 2 is a left side view and FIG. 3 is a front sectional view.

The roller bit 10 and the outer circumference gauge cutter 11 are provided so that three sets are adjacent to each other at intervals of 120 degrees in the rotation direction. The three sets of outer circumference gauge cutters 11 are provided at the same positions in the radial direction, but the three sets of roller bits 10 are provided at different positions in the radial direction. 3 sets of gauge cutters for outer circumference 11
The circular center line formed by the sharp outer peripheral edge of the roller bit 10 is neither parallel nor orthogonal to the axis of the cutter face 8, but the circular center line formed by the sharp outer peripheral edge of the roller bit 10 is the axis of the cutter face 8. It is orthogonal to the core line.

The front end face 12 of the cutter face 8 is formed in a plane orthogonal to the axial direction. The outer peripheral gauge cutter 11 is housed rearward of the front end face 12, but a part of the roller bit 10 projects forward of the front end face 12. The roller bit 10 is coaxially fixed to a rotating shaft 13 which is rotatably supported by a ball bearing (not shown). The outer circumference gauge cutter 11 of each set is composed of three abacus ball-shaped element bits 10a, 10b, 10c each having a center line orthogonal to the axis of the cutter face 8 as a concentric line.

As shown in FIG. 4, each abacus element bit 10a has a shape in which two truncated cones are integrated in the opposite direction, and the outer peripheral edge (blade edge) is sharply formed. There is. The intersection angle between the plane including the outer peripheral edge and orthogonal to the axis of the rotary shaft 13 and the shape line of the truncated cone center cross section is designed to be α. The intersection angle of the two shape lines appearing in the central cross section of the two truncated cones is designed to be 2α. The axial distance between the cutting edges of the axially adjacent element bits 10a and 10b is set to a length d. The diameter of the blade parallel plane portion of the roller bit 10 having no inclination angle α is represented by 2a, and the radial length of the blade inclined surface portion having the inclination angle α is e.

Behind the three sets of roller bits 10 and the outer circumference gauge cutter 11, inside the cutter face 7, FIG.
As shown in FIG. 3, discharge guide holes 15 and 16 are respectively provided in the axial direction. The positional relationship between the front end opening of the discharge guide hole 16 and the front end of the roller bit 10 or the front end face of the cutter face 8 is determined based on design constants described later.

A cutter face 8 is provided at the rear of the three pairs of roller bits 10 and outer circumference gauge cutter 11 in the rotational direction.
As shown in FIG. 2, discharge guide plates 17 and 18 are provided respectively. The discharge guide plates 17 and 18 are provided at the rear edges of the discharge guide holes 15 and 16 in the rotation direction. The discharge guide holes 15 and 16 are connected to an annular space between the outer casing 2 and the inner casing 3.

(Operation of First Embodiment) Next, the operation of the first embodiment will be described. The guide hole excavating casing 5 is rotationally driven, and the guide hole excavating bit 6 excavates a guide hole having a small diameter. Next, the rear inner casing 3a is rotationally driven with the leading hole excavating casing 5 as the central axis. The front inner casing 3b, which is rotationally connected to the rear inner casing 3a, rotates. Front inner casing 3b
The cutter face 8 and the cutter face 7, which are connected to, rotate.

The roller bit 10 and the outer circumference gauge cutter 11 provided on the cutter face 8 rotate,
The outer peripheral gauge cutter 11 excavates mainly so as to form a cylindrical peripheral surface of a small diameter hole. The roller bit 10 is excavated mainly so as to form a circular cross section of a small diameter hole in front of the excavation. In parallel with such excavation, a water pipe is introduced into the excavation hole and buried under the ground, following the front conductor 1. The bending of the drill hole is corrected by the swing control of the front outer casing 2a and the front inner casing 3a.

Excavation chips excavated by the roller bit 10 and the outer circumference gauge cutter 11 pass through the discharge guide holes 15 and 16 together with water sprayed from the tip of the guide hole excavation casing 5, and the outer casing 2. Is sent to the annular space between the inner casing 3 and the inner casing 3, and is discharged rearward by the spiral blade 4. The boulders and boulders in the gravel ground are broken by the wedge action of the cutting edge separated by the length d of the roller bit 10. The diameter of the average particle diameter of the stone thus divided is approximated by the distance d between the cutting edges of the roller bit 10.

In order to analyze the motion of the crushed rock having such an average grain size, refer to FIG. The cutter face 8 that rotates counterclockwise in FIG. 2 is shown to rotate clockwise in FIG. 5 (ie, FIG. 2 is seen from the front, but FIG. 5 is seen from the rear). The rotation axis of the roller bit 10 is oriented horizontally at the positions a and e, at the positions b and d, at θ degrees and θ + π / 2 with respect to the horizontal, and vertically at the position c. A line orthogonal to the horizontal plane X-Z coordinate having the axis of the leading conductor 1 as the Z axis and passing through the intersection O of the X axis and the Z axis is taken as the Y axis. Intersection O
Is hereinafter referred to as the origin. The plane XY is aligned with the vertical excavation surface S at the deepest part of the excavation hole.

A circle C ₁ indicated by a dotted line is a locus of a contact point where the excavation surface S and the roller bit 10 roll on the excavation surface and come into contact with the excavation surface. For position c, θ = 0. The revolution angle of the roller bit 10 from position a to position b is +
θ. In FIG. 6, the contact point between the roller bit 10 at the position B and the excavation surface is represented by P ₁ . FIG. 7 is a diagram in which the roller bit 10 is projected in a circle. The rotation direction of the roller bit 10 is indicated by an arrow a. The break point of the broken line on the blade surface from the point P ₁ on the cutting edge circle C ₂ toward the rotation axis O _j is defined as P ₂ .

The angle between the line segment P ₁ P ₂ and the plane orthogonal to the rotation axis is the angle α shown in FIG. The point at the position where the point P ₂ is rotated by the angle β in the rotation direction is defined as P ₃ . Line segment P
The angle between ₁ P ₂ and the plane orthogonal to the rotation axis Oj is α. FIG. 8 shows the front view of FIG. 7 tilted by an angle θ. Put the foot of the perpendicular line drawn from the point P _{3 on the} axis of rotation Oj at the point P ₇
And P on the straight line P ₂ P ₇ and the perpendicular line descending from the point P _3
Set to ₅ .

As can be easily seen from FIG. 7, the line segment P ₃ P
The length of ₅ is a · sin (β). In FIG. 8, point P ₃
Perpendicular line of the leg, who defeated a vertical line passing through the point P ₅ from the show at the point P ₆ a. The length of the line segment P ₅ P ₆ is (line segment P ₃ P ₅ ) · sin
Since it is (θ), it is represented by the line segment P ₅ P ₆ = a · sin (β) sin (θ). If the angle between the straight line P ₃ P ₇ and the horizontal plane is γ, the line segment P ₅ P ₇ is horizontal, and the point P ₇ and the point P
_Since the difference with ₃ is the length P ₅ P ₆ , that is, the point P
Assuming that the foot of the perpendicular line from the point P ₇ to the horizontal line passing through ₃ is P ₈ , P ₇ P ₈ = P ₅ P ₆ , so sin (γ) = (segment P ₅ P ₆ ) / a = sin ( β) sin (θ) (1) Therefore,

[0038]

[Equation 1] The angle δ of the line on the blade surface extending from the point P _{3 in the} radial direction with respect to the horizontal plane is approximately δ = γ + α (3) when θ is near zero.

FIG. 9 is a plan view of the roller bit 10 at the position B where it revolves around its axis while forming the excavated surface S.
The distance between the front end of the discharge guide hole 16 and the excavation surface S is D. A foot of a perpendicular line dropped from the center of a sphere R having an average diameter d, which is now crushed rock, to the slope of the blade, that is, a contact point Q between such a sphere and the slope of the blade and a line extending from the contact point Q in the radial direction. Make a reasonable assumption that D ₁ is the distance between the point where the and the cutting edge meet. If the contact point Q when it coincides with the cutting edge line is behind the vertical plane including the point anterior to the front end line of the discharge guide hole 16 by a distance D ₁ , the ball R falls into the discharge guide hole 16, If not, the ball R does not fall into the discharge guide hole 16 but falls toward the bottom of the drill hole. The boundary point based on this assumption is represented by the point Q ₁ in FIG.

L = D−D ₁ (4) The quantity D ₂ expressed by (4) is defined. Since the rotation of the sphere R is not so fast, the coefficient of friction between the sphere R and the slope of the blade is a static friction coefficient, which is sufficiently large.
It may be considered that the roller bit 10 that rotates while dropping the inclined surface of the blade up to ₁ rotates together with the roller bit 10. The distance D ₃ from the point Q to the point Q ₁ is represented by the following approximate expression D ₃ = aβ ₂ (5). Here, β ₂ is the angle QP ₇ Q ₁ .

The acceleration received by the sphere R on which the gravitational acceleration g acts along the inclined surface of the blade is gsin
(Δ). Letting the mass of the sphere be M, the force F ₂ that the sphere receives along the slope is F ₁ = Mgsin (δ) -μMgcos (δ) (6) The revolution angular velocity of the roller bit 10 is ω , Roller bit 10
Let r be the radius of the revolution orbit of, the peripheral speed v near the outer circumference of the roller bit 10 is approximated by the following equation.

V = ωr (7) Therefore, the centrifugal force generated when the sphere rotates integrally with the roller bit 10 is

[0043]

[Equation 2] Is. This centrifugal force acts on the sphere R as a component in the direction toward the inclined surface of the blade portion, so if the component is F ₂ ,

[0044]

(Equation 3) Therefore, the force F acting in the direction of moving the sphere R is

[0045]

[Equation 4] Letting s be the radial coordinate on the slope of the blade, the equation of motion is

[0046]

(Equation 5) From equations (2) and (3), in the range where θ is small,

[0047]

(Equation 6) If the angular position coordinate of the point Q is β ₁ , the distance s by which the point Q moves in the radial direction on the roller bit 10 is

[0048]

(Equation 7) The integration range is from β ₁ to β ₂ . Equation (2),
Substituting (3),

[0049]

(Equation 8) Here, θ can be treated as a constant within a sufficiently good approximation range. The integration range is β ₁ = 0 to β ₂ = (r /
a) Since ωΔt, k = r / a

[0050]

## EQU9 ## This integration is performed with the radial initial coordinate set to zero and the radial initial velocity set to zero. As shown in FIG. 9, the rock at the moment when it is sandwiched between the excavated surface S and the adjacent cutting edge of the roller bit 10 and split by the wedge action is the same body as the roller bit 10 due to a sufficiently large frictional force between the excavation surface S and the roller bit 10. It is assumed that the rock slides in the radial direction of the roller bit 10 to a position in contact with the cutting edge of the roller bit 10 while rotating in the direction.
This assumption is a valid assumption. The distance that a sphere having a certain average particle diameter determined by the distance between the blade edges slides in the radial direction is e / cos
Although it is smaller than (α), it is e / cos (α) with a good approximation.

This length s is the above-mentioned e / cos (α)
The point that coincides with is the fall start point.

S = e / cos (α) (16) As can be seen from FIGS. 9 and 10, the distance L between the drop point Q ₁ and the excavation surface S is approximately L = e + {a−a · cos (kωΔt)} = e + a {1-cos (kωΔt)} (17) The variable Δt in this equation can be obtained from the equations (16) and (17). If the distance between the excavation surface S and the front end face of the discharge guide hole 16 is D, a sufficient condition for guiding the rock ball falling from the roller bit 10 to the discharge guide hole 16 is given by the following formula. To be done.

[0053]

[Mathematical formula-see original document] This equation (19) is a general equation although it is approximate with respect to time t in the range in which θ is close to zero. Where d
Is the average particle size (diameter) of the rock sphere. In the above, e
Is sufficiently smaller than a, so (a + e) is approximated by a.

When D is smaller than the minimum value of L, all the rock balls are guided to the discharge guide hole 16 within the above range.
If the design value of L is too small, the excavation efficiency is poor. Conversely, L
If the design value of is too large, the excavation efficiency will be good, but the amount of excavated rock that falls and accumulates at the bottom of the excavation hole will be large, which will hinder excavation. Therefore, the value L is treated as a design value, which is a design constant empirically determined by experiments.

Next, a specific numerical value will be put into the parameter for consideration. The friction coefficient is zero, each revolution speed is 20 rpm, that is, a speed (2/3) π per second, the ratio of the radius a of the roller bit 10 to the revolution radius r is 3, the revolution radius is slightly more than 40 cm, and the wedge angle of the roller bit 10 is half. Let α be 30 degrees, and use equation (8)
The centrifugal acceleration obtained by dividing the centrifugal force represented by
The acceleration multiplied by cos (α) appearing in 0) is 400 cm
/ Sec · sec, gravitational acceleration g is 1000c
If m / sec · sec, sin (β) is 0.0
0, 0.03, 0.06, 0.09, 0.12, 0.1
5, 0.18 positions, that is, the acceleration A at five points up to the position where the contact point between the roller bit 10 and the excavation surface S makes a strong rotation of 10 degrees, the acceleration curves are shown for six θ in a small angle range. It is as shown in FIG.

FIG. 11 shows the case where the friction coefficient μ = 0.1. When the contact point with the excavation surface S rotates up to the point where β reaches a maximum value of 0.20, sin θ has a maximum value of 0.1.
In case of, the acceleration A shows the maximum value, about 404 cm / sec
・ It becomes sec. When the centrifugal force component is added to this, about 800
cm / sec · sec.

Next, when β = 0.05, the friction coefficient μ
Table 1 shows the acceleration A when sin and sin θ are changed. Table 2 shows the acceleration A when β and μ are taken into consideration by fixing sin θ = 0.04.

[0058]

[Table 1]

[0059]

[Table 2] From these tables, for example β = 0.05, friction coefficient μ =
0.1, acceleration at sin θ = 0.06 about 30
Consider using 0. Adding the centrifugal acceleration component 400,
Consider acceleration at 700 cm / sec.sec. Assuming that S in the equation (16) is 2 cm, the following equation is obtained.

[0060]

[Equation 11] During the time Δt obtained from
It will rotate about 5 degrees. Therefore, the drop point Q1
The distance L between the excavation surface and the excavation surface S is approximately calculated from the equation (18),
When 0.1 is selected as the friction coefficient μ, the above calculation is repeated and the distance L is about (e + 0.09a).

The experimental machine shown in FIGS. 2 and 3 has a distance d between the cutting edges.
= 3 cm, e = 1.8 cm, and a = 11 cm. Calculating for a friction coefficient μ = 0.1, L = 2.8
Becomes As a result of the experiment using the experimental machine, when D = 2.0, it was possible to excavate without the retention of the crushed particles in the lower part. Since this value is smaller than the theoretical value when the friction coefficient is 0.1, it can be seen that the prevention of the falling of the crushed particles to the lower portion is too sufficient. However, if the friction coefficient becomes larger, L becomes slightly larger than 2.8 cm.

Since the actual friction coefficient will be 0.1 or a little larger than this, the actual length L is 2.8 cm.
It should be bigger. However, as can be seen from the analysis, the numerical values are also in the range of small values of θ from 0 degree to about 10 degrees. Therefore, the greater the change in θ, the greater the length L. However, θ =
In the vicinity of 0, all the crushed particles should be picked up. That is, θ =
About 90, θ = 270, crushed particles that could not be picked up were θ
Since it can be lifted up to = 0 degree and θ = 180 degrees, it can be picked up again at that time. Therefore, in the above embodiment, D smaller than L may be 3 cm or less.

(Embodiment 2) Embodiment 2 relates to a drill bit shown in FIG. 4 of a small diameter pipe excavator. Discharge guide hole 16
The front end face of the cutter face 8 is not necessarily the cutter face 8 in the first embodiment.
Does not match the front face of the. In the second embodiment, the front end face of the discharge guide hole 16 coincides with the front end face of the cutter face 8 of the front conductor 2. During the actual excavation in which the slope of the roller bit 10 plunges into the ground from the rock surface, D is e or a value close to this, so in the above equation (18), D = e (20) is approximated. can do. This equation (20) and equation (1
The maximum value of the value e can be obtained from 8). It can be seen that it is realistic to design such a maximum value as the value of e from the consistency between the theoretical analysis and the experimental result.

(Embodiment 3) Embodiment 3 relates to a drill bit shown in FIG. 4 of a small-diameter pipe excavator. Discharge guide hole 16
The front end face of No. 1 does not necessarily match the front end face of the cutter face 8 in the first and second embodiments. In the third embodiment, the front end face of the discharge guide hole 16 is substantially the same as the front end face of the cutter face 8 of the front conductor 2. In this way, the front end opening of the discharge guide hole 16 is matched or substantially matched with the front end face of the cutter face 8, and the radial length e of the blade slope portion of the roller bit 10 is set to the blade tip distance of the roller bit 10. Design smaller than d.

Such a design is appropriate in view of the fact that the crushed particles are less likely to fall as the diameter is larger and the theoretical analysis in which D becomes a value close to L. If d is slightly larger than e, then θ =
In the case of 90 degrees, the fall of the crushed particles can be prevented, but since θ is a variable, it is preferable to make d relatively larger than e. The results obtained by the experimental machine with d = 3.0 cm and e = 1.8 cm show that d is relatively larger than e.
This point also agrees with the theoretical analysis with the variable.

(Other Embodiments) The equation (20) has parameters such as the rotational speed ω of the excavator (bit revolution angular velocity), the bit revolution radius r, the bit rotation radius a, and the ratio r.
/ A (= k), a distance d between adjacent pairs of blade edges, and a wedge angle 2α of the blade edges. Therefore, when designing to satisfy the equation (21), the value D is first determined, and ω, r, a,
The values of d and α can be used as design constants. However, since the radius r is a value that is automatically determined by the determined diameter value of the water pipe, the ratio k is strongly limited in terms of excavation efficiency. Further, the revolution angular velocity is also strongly limited by the power of the driving unit. Therefore, D becomes an appropriate design constant. In this case, since e is strongly restricted by D, e is also one of the design constants, but is designed in consideration of the relationship with the wedge angle 2α.

[0067]

According to the present invention, the following effects are exhibited. Since an appropriate value is selected as the design constant, the amount of falling stones can be dramatically reduced. Further, since the size of e, D, or L is determined from the relationship with the size of the crushed particles, the crushing force can be maintained even if the value of θ changes.

[Brief description of drawings]

FIG. 1 is a front view showing a first embodiment of a small-diameter pipe excavation propulsion machine used in the small-diameter pipe excavation propulsion method of the present invention.

FIG. 2 is a left side view of FIG.

FIG. 3 is a partial front view of FIG.

FIG. 4 is a plan view of the roller bit 10.

5 is a bird's-eye view showing the positional relationship between the excavated surface and the roller bit 10 at each rotational position. FIG.

FIG. 6 is an enlarged oblique-axis projection view showing a positional relationship between one rolling contact point where the excavation surface and the roller bit 10 are in contact with each other and one rotation position of the roller bit 10.

FIG. 7 shows a positional relationship between the excavated surface and the roller bit 10 at an arbitrary rotational position, and the oblique axis projection is represented by an angle corresponding to the rotational angle of the roller bit 10 as represented by a circle. It is a figure.

8 is a geometrical analysis diagram in the center cross section of the roller bit 10 at an arbitrary rotation position with reference to the plane cut along the line VIII-VIII of FIG. 7.

FIG. 9 is a plan view showing the positional relationship between the excavation surface and the roller bit 10 at an arbitrary rotational position.

FIG. 10 is a geometric analysis oblique-axis projection view showing the positional relationship between the excavation surface and the roller bit 10 at an arbitrary rotational position.

FIG. 11 is a graph in which biaxial coordinates are added to CG of an acceleration curve.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Leader conductor 2 ... Outer casing 3 ... Inner casing 8 ... Cutter face 10 ... Roller bit 12 ... Front end face 14 ... Ejecting guide hole α: Half of wedge angle of the roller bit, e: Blade part of the roller bit Radial length of slope part ω: Revolution angular velocity of the roller bit θ: Angular coordinates of the roller bit r: Revolution radius of the roller bit a: Radius of the roller bit k: r / a μ: Excavation rock Friction coefficient between the roller bit and the slope surface g: Gravitational acceleration β: {kω · (time as a design constant from the reference time point) + 2nπ} (that is, revolution rotation angle position coordinate as a design constant of the roller bit) n: integer

Claims (3)

[Claims] 1. A front conductor (1) comprising an outer casing (2) and an inner casing (3), and a front end portion of the front conductor (1) connecting the outer casing (2) and the inner casing (3). Cutter face (8)
A plurality of sets of roller bits (10) provided on the cutter face (8) so as to be able to rotate while revolving with the cutter face (8), and the cutter for discharging excavated material excavated by the roller bits. A small-diameter pipe excavation propulsion method using a small-diameter pipe excavation propulsion machine, which comprises a discharge guide hole (16) provided on the face and having an open front end, wherein θ is a constant and the integration range is from 0 second to Δt seconds. Δt obtained by the following equation up to s = e / cos (α) α: Half the wedge angle of the roller bit, e: Radial length of the slope of the blade of the roller bit ω: Revolution angular velocity of the roller bit θ: Of the roller bit Angular coordinates r: Radius of orbit of the roller bit a: Radius of the roller bit k: r / a μ: Coefficient of friction between excavated rock and slope of the roller bit g: Gravitational acceleration β: {kω ・ (reference Time as a design constant from the time point) + 2nπ} (that is, revolution rotation angle position coordinate as a design constant of the roller bit) n: defined by the following equation using an integer L = e + a {1-cos (kωΔt)} For the length L, The discharge guide hole (16) has a relationship defined by
A small-diameter pipe excavation propulsion method, which comprises excavating with a distance D between the excavation surface and the excavation surface being excavated. 2. A front conductor (1) comprising an outer casing (2) and an inner casing (3), and a front end portion of the front conductor (1) connecting the outer casing (2) and the inner casing (3). Cutter face (8)
And a discharge guide hole (16) provided in the cutter face for discharging a drilling material and having an open front end, the drill bit of a small diameter pipe drilling propulsion machine, wherein the drilling bit is the cutter. The cutter face (8) is free to rotate while revolving with the face (8).
Is a roller bit (10) provided with a plurality of sets, and Δt is obtained by the following equation where θ is a constant and the integration range is from 0 second to Δt seconds: s = e / cos (α) α: Half of the wedge angle of the roller bit, e: radial length of the blade slope of the roller bit ω: revolution angular velocity of the roller bit θ: angular coordinate of the roller bit r: revolution radius of the roller bit a : Radius of the roller bit k: r / a μ: coefficient of friction between excavated rock and slope of the roller bit g: gravitational acceleration β: {kω · (time as design constant from reference time point) + 2nπ} (That is, the revolution rotation angle position coordinate as the design constant of the roller bit) n: The following equation using an integer L = e + a {1-cos (kωΔt)} 12] Obtained from An excavating bit for a small-diameter pipe excavating machine, wherein the maximum value e is designed as the length in the radial direction of the slope of the blade of the roller bit. 3. A front conductor (1) comprising an outer casing (2) and an inner casing (3), and a front end portion of the front conductor (1) connecting the outer casing (2) and the inner casing (3). Cutter face (8)
And a discharge guide hole (16) provided on the cutter face and having an open front end for discharging the excavated material excavated by the roller bit (10). This drill bit revolves with the cutter face (8) while freely revolving around the cutter face (8).
A plurality of sets are provided in the roller bit (10), and the front end opening of the discharge guide hole (16) is positioned so as to match or substantially match the front end surface of the cutter face (8). An excavating bit for a small-diameter pipe excavator, characterized in that the radial length of the blade sloped surface of (10) is designed to be smaller than the distance between blade edges of the roller bit (10).