JP2013209828A - Tip bit and drilling apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tip bit which can drill a hole with a high degree of accuracy along a desired drilling locus by improving straightness of the tip bit in a horizontal direction during straight drilling and curved drilling, and a drilling apparatus.SOLUTION: A tip bit 2, which has a tip part provided with a taper surface 20 inclined in a tapered shape, is inserted in a rotating or nonrotating state into ground to drill a hole. A protrusive streak 7 linearly elongated in a direction of inclination is provided in an approximately central position in a width direction on the taper surface 20. A swelling part 5 assuming a chevron shape in a cross-sectional view is provided on the taper surface 20, and a crest part 53 of the swelling part 5 configures the protrusive streak 7.

Description

  The present invention relates to a drilling device capable of performing linear drilling and curved drilling, and a tip bit attached to the drilling device.

  Conventionally, for example, in order to inject a chemical solution or the like below a building by performing a curved hole drilling obliquely from the ground surface toward the lower part of the building, and then performing a straight hole drilling by changing the direction in the horizontal direction. A hole drilling device capable of forming a single hole is known (see, for example, Patent Document 1).

  As shown in FIG. 16, this type of drilling device includes a hollow hole 101 that can be bent, and a tip bit 102 attached to the tip of the drill tube 101. The distal end surface is formed on a tapered surface 103 that is inclined so that the thickness decreases from the drilled tube 101 side toward the distal end side. When drilling with the tip bit 102, if the boring machine 104 installed on the ground is propelled through the ground without rotating the drilling tube 101 and the tip bit 102, the tip bit 102 has a specific direction via the tapered surface 103. Since the earth pressure from the earth acts continuously, the traveling direction of the tip bit 102 changes at any time. As a result, the tip bit 102 is propelled into a curved shape and curve drilling becomes possible. On the other hand, when propelling the ground while rotating the drilling tube 101 and the tip bit 102, the direction of the earth pressure acting on the tapered surface 103 of the tip bit 102 is canceled by the change around the rotation axis. Protruded in a straight line, straight drilling becomes possible.

JP-A-8-120661

  However, when the tapered surface 103 of the tip bit 102 is a flat inclined surface as in the hole drilling device 100 configured as described above, there are the following problems. First, at the time of curved hole drilling, when propelling the ground without rotating the tip bit 102, earth and sand, foreign matter M, etc. existing in the ground are applied to the tapered surface 103 of the tip bit 102 as shown in FIG. Since they are in proper contact, the direction of the tip bit 2 may change from a predetermined direction due to the influence of the foreign matter M or earth and sand. Even if the tip bit 102 is continuously pushed in this state, the traveling direction of the tip bit 102 in the horizontal direction (shown in FIG. 16) changes, and the tip bit 102 bends in the left-right direction with respect to the pushing direction. There is a problem that the drilling locus by 102 deviates from the desired drilling locus.

  Further, even when straight drilling is performed, when the tip bit 102 is pushed into the ground while being rotated, a space 104 in which no drilling is performed is formed in the rotated tip bit 102 as shown in FIG. However, since this space 105 occupies a large area, a large amount of earth and sand and foreign matter M accumulate in this space 105. As a result, foreign matter M and earth and sand contact the tapered surface 103 of the tip bit 102 during drilling. The direction of the tip bit 102 may change. Then, similarly, the advancing direction in the horizontal direction (shown in FIG. 16) of the tip bit 102 changes, and even if the tip bit 102 is to be propelled straight, the tip bit 102 bends left and right with respect to the propulsion direction. There is a problem that the drilling locus by the tip bit 102 deviates from the desired drilling locus.

  The present invention has been made paying attention to the above-mentioned problems, and improves the straightness of the tip bit in the horizontal direction even when straight drilling and curved drilling, so that the accuracy along the desired drilling locus is improved. An object of the present invention is to provide a tip bit and a drilling device capable of performing high drilling.

  The above-mentioned object of the present invention is a tip bit that has a tapered surface that is tapered at the tip portion, and performs drilling by being inserted into the ground in a rotated state or a non-rotated state, on the tapered surface. Is achieved by a tip bit provided with a ridge extending linearly in the inclined direction at a substantially central position in the width direction.

  In a preferred embodiment of the present invention, a raised portion having a mountain shape in cross section is provided on the tapered surface, and the top of the raised portion forms the protruding shape.

  In a further preferred aspect of the present invention, the raised portion is characterized in that the angle of the top is not more than 150 degrees.

  In a further preferred aspect of the present invention, the raised portion is formed in a triangular shape in sectional view.

  In another preferred embodiment of the present invention, an elongated plate-like protrusion having a flat upper surface is provided on the tapered surface, and the protrusion constitutes the protrusion.

  In a further preferred embodiment of the present invention, a carbide tip is embedded in the protrusion.

  The above object of the present invention can also be achieved by a drilling device in which the tip bit of the above configuration is attached to the tip of the drilling tube.

  According to the tip bit and the hole drilling device according to the present invention, the straightness in the horizontal direction of the tip bit is improved even during straight hole drilling and curved hole drilling, so that the accuracy along the desired hole trajectory is high. Drilling can be performed.

It is the schematic which shows the whole structure of the drilling apparatus using the front-end | tip bit which concerns on one Embodiment of this invention. It is a top view of a tip bit. It is a side view of a tip bit. It is explanatory drawing explaining the advancing direction of the front-end | tip bit at the time of curve drilling. It is sectional drawing of a protruding part. It is explanatory drawing which shows the state of the front-end | tip bit at the time of linear drilling. It is explanatory drawing which shows the state of the front-end | tip bit at the time of curve drilling. It is a top view of the tip bit of other examples. It is a side view of the tip bit of another example. It is sectional drawing of the protruding part of another example. It is experimental data of the tip bit concerning the present invention. It is the experimental data of the tip bit concerning a prior art. It is a top view of the tip bit concerning other embodiments of the present invention. It is a side view of the tip bit concerning other embodiments of the present invention. It is explanatory drawing which shows the state of the front-end | tip bit at the time of curve drilling. It is the schematic which shows the whole structure of the drilling apparatus using the front-end | tip bit which concerns on a prior art. It is explanatory drawing which shows the state of the front-end | tip bit at the time of curve drilling. It is explanatory drawing which shows the state of the front-end | tip bit at the time of linear drilling.

  Hereinafter, actual forms of the present invention will be described with reference to the accompanying drawings. FIG. 1 is a schematic view showing an overall configuration of a drilling device 1 to which a tip bit 2 according to the present invention is applied, and FIGS. 2 and 3 show a plan view and a side view of the tip bit 2, respectively.

  The drilling device 1 to which the tip bit 2 according to the present invention is applied is not limited to a specific form, and the drilling tube 3 is not rotated by a boring machine 4 installed on the ground. By pushing into the ground in a rotating state, a conventionally known drilling device that drills the ground into a curved or linear shape by the tip bit 2 can be used.

  The hole drilling tube 3 is a hollow cylindrical tube that can be bent, and has a cavity 30 that can supply various liquids and insert various instruments in the entire tube. This drilled tube 3 can be formed, for example, by connecting a plurality of cylindrical bodies so as to be sequentially added in series according to the depth of insertion into the ground. As the material of the drilling tube 3, a known material such as a metal or a resin can be used. Further, the inner diameter and the wall thickness of the hole drilling tube 3 may be appropriately set according to the strength of the ground, the soil quality, etc., and are not limited.

  The tip bit 2 is attached to the tip portion of the drilled tube 3. As shown in FIG. 2 and FIG. 3, a substantially elliptical tapered surface 20 is provided at the distal end portion of the distal end bit 2 so as to be tapered so that the thickness decreases from the drilled tube 3 side toward the distal end side. It has been. As a result, as shown in FIG. 4, the tip bit 2 is not rotated in the ground so that the tapered surface 20 faces vertically downward Z <b> 1 with respect to the propulsion direction X of the tip bit 2. When pushed in, a force of Z2 in the vertical direction with respect to the propulsion direction X acts on the tip bit 2 at any time due to the earth pressure P that continuously acts on the tapered surface 20. Then, the traveling direction of the tip bit 2 is directed upward with respect to the propulsion direction X, and the tip bit 2 is pushed in the inclined direction Y of the tapered surface 20. As a result, the tip bit 2 protrudes obliquely downward as shown in FIG. It is propelled into a curved shape and curved drilling is performed.

  On the other hand, when the tip bit 2 is pushed into the ground in a rotating state, the earth pressure P from the specific direction acting on the tapered surface 20 of the tip bit 2 is canceled by the change around the rotation axis. Therefore, as a result of the tip bit 2 being propelled linearly along the propulsion direction X, straight drilling is performed. 2 and 3, reference numeral 21 denotes a tip jig, and reference numerals 22 and 23 denote tip ends of the tip bit 2 on the tapered surface 20 side and the opposite side through the drilled tube 3 respectively. The fluid supplied to the cavity 25 formed in the bit 2 can be injected into the ground through the injection ports 22 and 23.

  On the tapered surface 20 of the tip bit 2, a raised portion 5 protruding higher than the tapered surface 20 is provided. In the present embodiment, as shown in FIGS. 2 and 3, the raised portion 5 has a mountain shape in cross section, and is preferably made of steel such as cast iron, mild steel, and hard steel. The raised portion 5 has a triangular shape in cross-section and includes a pair of left and right side portions 50, 50 extending from the tapered surface 20 and a pair of front and rear front portions 51 and 52, and is an example shown in FIGS. 2 and 3. Then, the side part 50, the front part 51, and the rear part 52 are each plate-shaped, and the inside of the raised part 5 is hollow. The raised portion 5 is formed as a separate member from the tapered surface 20, and may be fixed on the tapered surface 20 by a well-known fastening technique such as welding or a screw, or may be integrally formed with the tapered surface 20. Also good. In addition, the cross-sectional view shape of the raised portion 5 is not particularly limited to a polygonal shape in addition to the triangular shape as long as it has a sharp pointed shape.

  The pair of left and right side surface portions 50 are highly inclined toward the center of the width of the tapered surface 20 at the same inclination angle, respectively, and the pointed linear top portions 53 where the both side surface portions 50 intersect each other are the tapered surface 20. Located in the center of the width direction. As a result, the ridge 7 extending linearly in the tilt direction is provided at the center position in the width direction on the tapered surface 20.

  As shown in FIG. 5, the angle α of the top 53 of the raised portion 5, that is, the intersecting angle α at which the both side surface portions 50 intersect with each other is only required to be provided with the ridge 7 extending linearly on the tapered surface 20. However, if the angle α is large, the sharpness of the tip of the raised portion 5 is weakened, and there is a possibility that the same problem as a tapered surface with a flat surface as in the prior art may occur. In consideration of the accuracy, it is preferably 150 degrees or less. Further, the width w of the raised portion 5 is preferably set smaller than the width b (shown in FIG. 2) of the tapered surface 20 in consideration of the accuracy of drilling. Further, the height h of the raised portion 5 is such that the top 53 of the raised portion 5 does not protrude beyond the maximum diameter R (shown in FIG. 3) of the tip bit 2 in consideration of the accuracy of drilling. The size is preferably set.

  In the example shown in FIGS. 2 and 3, the surface shape of the tapered surface 20 is formed in a straight line in a side view, but may be formed in, for example, a curved shape or a polygonal shape. In the example shown in FIGS. 2 and 3, the raised portion 5 is formed in a sharp pointed shape and the apex portion 53 is linear in a plan view. As shown, the top 53 may be a flat surface with some width.

  In the example shown in FIGS. 8 and 9, the raised portion 5 is formed in a trapezoidal shape in cross section, and the center of the width of the planar top 53 is located at the center of the tapered surface 20 in the width direction. Thereby, also in the example shown in FIG. 8 and FIG. 9, the protrusion 7 that extends linearly in the inclined direction is provided at the center in the width direction on the tapered surface 20. In the example shown in FIGS. 8 and 9, the raised portion 5 has a solid structure filled with the contents, and the injection port 22 is provided via the cavity 23 in the tip bit 2 and the cavity 24 in the raised portion 5. It is open. In the example shown in FIGS. 8 and 9, the raised portion 5 may be formed by a member different from the tapered surface 20 and fixed on the tapered surface 20 by a well-known fastening technique such as welding or a screw. The taper surface 20 may be integrally formed.

  Also, in the example shown in FIGS. 8 and 9, the angle α of the top 53 of the raised portion 5, that is, the crossing angle α (shown in FIG. 10) at which the side surface portions 50 intersect is only smaller than 180 degrees. Considering the accuracy of drilling, it is preferably 150 degrees or less. Further, the height h (shown in FIG. 10) of the raised portion 5 is set such that the top 53 of the raised portion 5 does not protrude beyond the maximum diameter R (shown in FIG. 9) of the tip bit 2. It is preferable. The width w (shown in FIG. 10) of the raised portion 5 is set to the same size as the width b (shown in FIG. 8) of the tapered surface 20 in the illustrated example. It may be set smaller.

  According to the drilling device 1 including the tip bit 2 having the above-described configuration, the taper surface 20 is provided with the raised portion 5 having a pointed cross-sectional mountain shape on the taper surface 20 of the tip bit 2. At the center position, a ridge 7 that extends linearly in the inclination direction is provided. Therefore, first, when propelling the tip bit 2 into the ground in a non-rotating state at the time of curved hole drilling, as shown in FIG. Even in the case of contact with the taper surface 20, the foreign matter M and earth and sand can be smoothly dispersed outwardly at the ridge 7 that linearly extends substantially at the center in the width direction of the tapered surface 20. Resistance (influence) due to can be reduced. Therefore, it can suppress that the direction of the front-end | tip bit 2 changes from a predetermined direction, and can maintain the state where the taper surface 20 has faced the front straight with respect to the propulsion direction X. As a result, the tip bit 2 can be prevented from changing in the horizontal direction of the tip bit 2 from the initially assumed direction of travel, such as the tip bit 2 bending in the left-right direction with respect to the propulsion direction X. The straightness with respect to the direction can be improved, and it is possible to perform highly accurate drilling along a desired drilling locus.

  On the other hand, when propelling the tip bit 2 into the ground in a rotating state during straight drilling, as shown in FIG. 6, the tip bit in the rotated state is equivalent to the presence of the raised portion 5 on the tapered surface 20. The space 55 formed by 2 and not drilled is reduced. Therefore, it is possible to suppress a change in the direction of the tip bit 2 caused by the influence of earth and sand or foreign matter accumulated in the space 55. Therefore, since the tip bit 2 can be propelled straight along the propulsion direction X without bending left and right with respect to the propulsion direction X, the straightness in the horizontal direction of the tip bit 2 is improved even during straight drilling. Therefore, it is possible to perform drilling with high accuracy along a desired drilling locus.

The inventors of the present application use the tip bit 2 according to the present invention shown in FIGS. 2 and 3 described above to confirm the drilling locus by the tip bit 2 when the ground is subjected to curved drilling and straight drilling. The test for was done. In the test, first, the tip bit is propelled linearly downward from the ground surface (up to about 5 m), and then the tip bit is propelled in a curved shape, and then changed in the horizontal direction to be linear. Promoted the tip bit. As a result, drilling locus data as shown in FIG. 11 was obtained for the tip bit 2 according to the present invention. 11A shows the excavation locus in the horizontal direction, and FIG. 11B shows the excavation locus in the vertical direction. Further, as a comparative example, the data of the drilling locus data of the tip bit when the tip bit having a tapered surface with a flat surface as in the prior art is formed in a curved hole and a straight hole in the ground are shown in FIG. Shown in Similarly, FIG. 12A shows an excavation locus in the horizontal direction, and FIG. 12B shows an excavation locus in the vertical direction. The test conditions are as follows.
-Tip bit dimensions (length L x maximum diameter R): 190 mm x 120 mm
-Tapered surface dimensions (length a x width b): 170 mm x 120 mm
-Thickness t of the side plate portion of the raised portion: 4.5 mm
-Angle α at the top of the raised portion: 120 °
-Insertion angle φ from the ground surface of the tip bit into the ground:
Example 1 (φ1) of FIG. 8: 16 °
Example 2 (φ2) of FIG. 8: 32 °
Comparative example (φ) in FIG. 9: 20 °
-Insertion speed of tip bit into the ground: 0.5 to 3.0 m / min

  As can be seen from FIGS. 11 and 12, when the tip bit 2 according to the present invention is used, the tip bit 2 has a traveling direction in the horizontal direction in both cases of curved drilling and straight drilling. It can be confirmed that the propulsion is propelled straight through the ground with almost no change, that is, almost without bending left and right with respect to the propulsion direction. Therefore, according to the tip bit 2 according to the present invention, the straightness in the horizontal direction of the tip bit 2 is improved even during linear drilling and curved drilling, so that the accuracy along the desired drilling locus is high. Drilling can be realized.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these, A various change is possible unless it deviates from the meaning of this invention. For example, a plate-like protrusion 6 as shown in FIGS. 13 and 14 may be provided on the tapered surface 20 of the tip bit 2 in place of the raised portion 5. The protrusion 6 is formed in an elongated shape with a flat upper surface, and the center of the width is located at the center of the taper surface 20 in the width direction. Thereby, the planar protrusion 7 linearly extending toward the inclination direction is provided at the center position in the width direction on the tapered surface 20. The width W of the projecting portion 6 is preferably 5 mm to 25 mm, and the height H of the projecting portion 6 is the maximum diameter R of the tip bit 2 (shown in FIG. 14) in consideration of the accuracy of drilling. It is preferable that the size is set so that the upper surface of the protrusion 6 does not protrude outward. In addition, a cemented carbide chip (not shown) may be embedded in the protrusion 6. By embedding the cemented carbide tip, it is possible to prevent the projections 6 from being worn away by friction with the earth and sand during rotary drilling, and thus the projections 6 can be protected.

  Also in the embodiment shown in FIG. 13 and FIG. 14, the ridge 7 that extends linearly in the inclined direction is provided at the central position in the width direction of the tapered surface 20 of the tip bit 2. The protrusion 7 acts as a guide member that improves the straightness of the tip bit 2 in the horizontal direction when drilling. That is, at the time of curved hole drilling, as shown in FIG. 15, even when foreign matter M or earth and sand existing in the ground contacts the tapered surface 20 of the tip bit 2, the flow of foreign matter M and earth and sand is caused to flow in the ridge 7. Since it can disperse | distribute outside, the resistance (influence) by the foreign material M with respect to the taper surface 20, earth and sand, etc. can be reduced. Therefore, the direction of the tip bit 2 can be prevented from changing from a predetermined direction, and the state in which the tapered surface 20 faces straight in front of the propulsion direction can be maintained. It is possible to prevent the traveling direction in the horizontal direction of the tip bit 2 from changing from the initially assumed traveling direction, such as bending left and right with respect to the direction. Therefore, it is possible to improve the straightness of the tip bit 2 in the horizontal direction, and it is possible to perform drilling with high accuracy along a desired drilling locus.

  Further, in the case of linear drilling, the space 55 in which no drilling is formed by the tip bit 2 in a rotating state is reduced by the presence of the protrusion 6 on the tapered surface 20. Therefore, as a result of suppressing the change in the direction of the tip bit 2 caused by the influence of earth and sand accumulated in the space 55 and the foreign matter M, the tip bit 2 is not bent left and right with respect to the propulsion direction. It can be propelled straight along the propulsion direction. Therefore, even in the case of linear drilling, the straightness in the horizontal direction of the tip bit 2 can be improved, and highly accurate drilling along a desired drilling locus can be performed.

DESCRIPTION OF SYMBOLS 1 Drilling device 2 Tip bit 5 Raised part 6 Projection part 7 Projection 20 Tapered surface 53 Top part

Claims (7)

A tip bit having a tapered surface tapered at the tip and drilling by being inserted into the ground in a rotating state or a non-rotating state,
A tip bit provided with a ridge extending linearly in the inclined direction at a substantially central position in the width direction on the tapered surface.   The tip bit according to claim 1, wherein a raised portion having a mountain shape in cross section is provided on the tapered surface, and a top portion of the raised portion forms the protruding shape.   The tip bit according to claim 2, wherein an angle of the top of the raised portion is 150 degrees or less.   The tip bit according to claim 2 or 3, wherein the raised portion is formed in a triangular shape in sectional view.   2. The tip bit according to claim 1, wherein an elongated plate-like protrusion having a flat upper surface is provided on the tapered surface, and the protrusion forms the protrusion.   The tip bit according to claim 5, wherein a carbide chip is embedded in the protrusion.   A drilling device in which the tip bit according to any one of claims 1 to 6 is attached to a tip portion of the drilling tube.

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