JP6606848B2 - Drilling tools - Google Patents

Description

  The present invention relates to an excavation tool in which an excavation tip is attached to the outer periphery of a distal end portion of a tool body rotated around an axis.

  As such an excavation tool, for example, Patent Document 1 discloses the implantation direction of the outermost cemented carbide button-shaped implant blade (excavation tip) into the bit holder (tool body), and the bit vertical axis (axis). In addition, it is described that is arranged to be tilted outward and tilted in the same direction as the bit rotation direction (tool rotation direction). According to such an excavation tool, it is possible to prevent the occurrence of breakage and the like by avoiding bending stress acting on the excavation tip due to rotation of the tool body during excavation.

Japanese Utility Model Publication No. 63-040544

  By the way, in such a drilling tool, when a certain amount of wear occurs in the drilling tip, the cutting edge is re-polished to restore the drilling performance. Usually, such re-grinding is performed by placing the rotation axis of the re-grinding wheel perpendicular to the tip center line of the drilling tip, and the tip center line is on a plane including the axis of the tool body. Then, the rotational axis of the regrinding wheel is arranged with reference to the axis of the tool body.

  However, like the excavation tool described in Patent Document 1, the implantation direction of the excavation tip into the tool main body is inclined to the outside of the tool main body and the tool rotation direction, and the tip center line of the excavation tip is the tool main body. It is difficult to accurately arrange the rotational axis of the regrinding wheel with reference to the axis of the tool body when the rotational position of the regrinding wheel is relative to the axis of the tool. For this reason, the cutting edge of the excavation tip is re-polished to strain and is likely to be damaged, and the life of the excavation tool after re-polishing may be shortened.

  The present invention has been made under such a background, and improves the workability of re-polishing even in an excavation tool in which the excavation tip is inclined to the outer peripheral side of the tool body and the tool rotation direction side as described above. The aim is to provide a drilling tool capable of this.

In order to solve the above-described problems and achieve such an object, the present invention provides the above-described axis line whose diameter decreases as the outer peripheral portion of the tip surface of the tool body rotated around the axis line moves toward the tip side of the tool body. And the inner peripheral portion of the tip surface on the inner peripheral side of the gauge surface is a flat face surface perpendicular to the axis, and the gauge surface and the face The excavation tip is attached to the surface, and the excavation tip attached to the gauge surface is inclined so that the tip center line is directed toward the outer peripheral side of the tool body and the tool rotation direction side toward the tip end side in the axial direction. together are, in the gauge face is an outer peripheral portion of the front end surface of the tool body, adjacent to at least the tool rotational direction of the mounting portion of the excavation tip, flat seat surface perpendicular to the chip center line Is formed, the bearing surface is inclined to the rear end side of the axial direction toward the the outer circumferential side and the tool rotational direction of the tool body from said attachment portion, the face surface in the tool rotation direction It extends so that the outer peripheral part of this may be partially cut off, and cross | intersects the outer periphery of the said gauge surface, It is characterized by the above-mentioned .

  In the excavation tool configured as described above, since the tip center line of the excavation tip is inclined toward the tool rotation direction side toward the tip end side in the axial direction as in the excavation tool described in Patent Document 1, While the bending stress acting on the excavation tip can be reduced, a flat seat surface perpendicular to the tip center line of the excavation tip is adjacent to the excavation tip mounting portion on the outer peripheral portion of the tip surface of the tool body. Thus, when the excavation tip is repolished, accurate repolishing can be performed by arranging the rotation axis of the regrinding grindstone with reference to the seating surface. For this reason, even if the axis of the tool body and the tip center line are in a twisted positional relationship, it is possible to prevent the cutting edge of the drilling tip from being re-polished due to distortion and becoming easily damaged, thereby extending the life of the drilling tool. can do.

  By the way, when the outermost excavation tip is inclined also in the tool rotation direction as in the excavation tool described in Patent Document 1, the flour (drilling waste) generated by being crushed by the outermost excavation tip. Flows out along the inclination of the excavation tip so as to be guided to the tool rotation direction side. However, since the excavation tip is inclined so as to cover the tip surface of the tool body on the tool rotation direction side, it is difficult for discharged dust to be discharged. There is also a possibility that the excavation tip falls off due to wear on the outer peripheral surface, particularly around the mounting portion of the excavation tip.

Therefore, in the present invention, the seat surface is formed adjacent to at least the tool rotation direction side of the mounting portion of the excavation tip, so that the seat surface is located on the outer peripheral side of the tool body and the tool rotation direction side from the mounting portion. Since it will incline toward the rear end side in the axial direction of the tool main body as it goes to, a large space can be secured on the outer peripheral side of the cutting edge of the excavation tip and the tool rotation direction side. Therefore, it is possible to efficiently discharge the dust through this space, suppress wear of the tool body, prevent the excavation tip from dropping, and perform stable excavation over a long period of time.

  Further, particularly in such a case, by forming a discharge groove for dusting that opens in the seat surface on the tool rotation direction side of the excavation tip mounting portion on the outer periphery of the tool body, as described above. In addition, it is possible to more efficiently discharge the dust that has been discharged to the space on the tool rotation direction side of the cutting edge of the excavation tip, and further suppress wear of the tool body.

  Furthermore, by arranging the excavation tip attached to the outer peripheral portion of the tip surface of the tool body as described above so as to overlap with the portion having the maximum outer diameter at the tip portion of the tool body in the axial direction, The portion of the tool body tip portion having the maximum outer diameter can be protected from contact with the inner periphery of the excavation hole by the excavation tip to suppress the progress of wear on the tool body tip portion outer periphery. Accordingly, it is possible to prevent the excavation tip attached to the outer peripheral portion of the tip surface of the tool body from dropping off early due to the wear of the tool body tip, thereby further extending the tool life. .

  As described above, according to the present invention, the cutting edge of the excavation tip can be accurately re-polished to prevent the occurrence of defects and the like while suppressing bending stress acting on the excavation tip, and a long-life excavation tool Can be provided.

It is a perspective view which shows one Embodiment of this invention. It is the front view which looked at embodiment shown in FIG. 1 from the axial direction front end side. It is a side view of the X direction view in FIG. FIG. 3 is a partial side view as viewed in the Y direction in FIG. 2. It is ZQZ sectional drawing in FIG.

  1 to 5 show an embodiment of the present invention. In the present embodiment, the tool body 1 has a substantially bottomed cylindrical shape centering on the axis O with a steel material or the like, and the bottomed portion is a tip portion (right side portion in FIGS. 3 to 5). A female screw portion 2 is formed on the inner periphery of a cylindrical portion (skirt portion) which is a rear end portion (left side portion in FIGS. 3 to 5). Such an excavation tool has a rotational force in the tool rotation direction T around the axis O transmitted from the excavator through the excavation rod connected to the female screw portion 2, thrust in the axis O direction, and impact. The ground is excavated by the excavation tip 3 attached to the tip by force.

  The outer peripheral surface of the front end portion of the tool body 1 is a conical surface centered on the axis O after the cross section along the axis O increases in diameter in a concave curve shape from the rear end side in the axis O direction toward the front end. It is formed so as to further expand the diameter. Further, the distal end surface of the tool main body 1 is reduced in diameter as the inclination with respect to the axis O is steeper toward the distal end side than the conical surface formed by the distal end side of the outer peripheral portion of the distal end portion except for a seating surface described later. The gauge surface 4 is a conical surface centering on the axis O, and the inner peripheral portion of the tip surface on the inner peripheral side of the gauge surface 4 is a flat face surface 5 perpendicular to the axis O. .

  The excavation tip 3 is attached to the gauge surface 4 and the face surface 5. The excavation tip 3 is formed of a material harder than the tool body 1 such as cemented carbide, and in this embodiment, a rear end portion having a columnar shape centering on the tip center line C, and the tip center line C This is a button chip in which a rear end portion having a center on the top and a tip of a hemispherical tip having the same diameter are integrally sintered.

  Among these, a plurality of concave holes having a circular cross section as the attachment portion 6 of the excavation tip 3 are provided on the face surface 5 in parallel with the axis O, that is, perpendicular to the face surface 5 with a gap in the circumferential direction and radial direction (this embodiment) The excavation tip 3 is mounted by being inserted by brazing, press-fitting, or the like by inserting the rear end portion into these attachment portions 6 and projecting the blade edge from the face surface 5. Yes. The plurality of excavation tips 3 thus attached to the face surface 5 are arranged so that the rotation trajectories around the axis O of the blade edges overlap each other and cover the substantially entire face surface 5.

  In addition, a plurality of (9 in the present embodiment) circular recesses having a circular cross section are formed as attachment portions 7 at intervals in the circumferential direction on the gauge surface 4, and the excavation tip 3 is also attached to these attachment portions 7. The rear end portion is inserted and the cutting edge is protruded from the gauge surface 4 and is planted and attached by brazing or press fitting. However, the mounting portions 7 of these gauge surfaces 4 are positioned on a plane P whose center line of the concave hole is parallel to the plane including the axis O of the tool body 1 and slightly opposite to the tool rotation direction T. It is arrange | positioned so that it may extend to the outer peripheral side of the tool main body 1 as it goes to the front side with respect to the axis O direction.

  Accordingly, the excavation tip 3 attached to the attachment portion 7 is also inclined toward the outer peripheral side of the tool body 1 as shown in FIG. 5 as the tip center line C goes to the front end side in the axis O direction. At the same time, as shown in FIG. 4, it also tilts toward the tool rotation direction T side. The inclination angle of the tip center line C of the excavation tip 3 attached to the attachment portion 7 of the gauge surface 4 in the tool rotation direction T is perpendicular to the axis O and the cutting edge of the excavation tip 3 is as shown in FIG. The inclination angle θ with respect to the axis O when viewed from the straight direction passing through the center of the formed hemisphere is preferably in the range of 5 ° to 20 °, and more preferably in the range of 10 ° to 15 °.

  Further, on the gauge surface 4 which is the outer peripheral portion of the tip surface of the tool body 1, a planar seat surface 8 perpendicular to the tip center line C of the excavation tip 3 attached to each attachment portion 7 of the gauge surface 4 is provided. , Are formed adjacent to the mounting portion 7. In the present embodiment, these seating surfaces 8 extend from the side slightly opposite to the tool rotation direction T of the mounting portion 7 toward the tool rotation direction T, and the gauge surface 4 on the side opposite to the tool rotation direction T. The crossing ridge line part of the mounting part 7 is a semi-elliptical shape and extends so as to partially cut out the outer peripheral part of the face surface 5 on the tool rotation direction T side. 8 is open.

  Furthermore, in the present embodiment, the maximum outer diameter formed by the rotation locus around the axis O of the excavation tip 3 attached to the attachment portion 7 of the gauge surface 4 is set to be larger than the maximum outer diameter of the tool body 1. ing. That is, the diameter of the cylinder circumscribing the excavation tip 3 of the gauge surface 4 with the axis O as the center is the diameter of the outer peripheral edge of the gauge surface 4 (the gauge surface 4 and the tool main body, which is the maximum outer diameter in the tool body 1 in this embodiment). 1 of the outer peripheral surface of the tip end portion of the tip end portion of the outer periphery of the tip end portion of the tip end portion of the outer periphery of the tip end portion. As shown in FIG. 2, the cutting edge of the excavation tip 3 on the gauge surface 4 slightly protrudes from the tool body 1.

  Furthermore, in the present embodiment, the seating surface 8 where the mounting portion 7 that is a concave hole is opened is the direction of the axis O as it goes from the mounting portion 7 to the outer peripheral side of the tool body 1 and the tool rotation direction T side, as will be described later. 4 and the outer peripheral edge of the gauge surface 4 that has the maximum outer diameter at the tip of the tool body 1, and the mounting portion 7 is formed as shown in FIGS. 3 and 4. The gauge surface 4 is formed to a position slightly beyond the outer peripheral edge on the rear end side in the axis O direction. Therefore, the excavation tip 3 attached to the attachment portion 7 also slightly overlaps with the outer peripheral edge of the gauge surface 4, which is the portion having the maximum outer diameter, at the distal end portion of the tool body 1 in the axis O direction.

  As described above, the tool rotation direction of each attachment portion 7 of the gauge surface 4 is provided on the outer peripheral surface of the distal end portion of the tool body 1 formed so as to increase in diameter from the rear end side in the axis O direction toward the distal end side. Flour discharge grooves 9 are formed on the T side so as to cross and open the seating surfaces 8 respectively. These discharge grooves 9 are inclined in the same direction as the inclination of the tip center line C in a side view so as to be directed to the opposite side of the tool rotation direction T toward the rear end side in the axis O direction. In this embodiment, there are nine first discharge grooves 9A having a shallow groove depth and a short groove length, and second and third two discharge grooves having a deep groove depth and a long groove length. Three sets of 9B and 9C are formed in this order toward the opposite side of the tool rotation direction T.

  Among these, the first discharge groove 9A and the second discharge groove 9B adjacent to the opposite side to the tool rotation direction T of the first discharge groove 9A are open on the tool rotation direction T side of the seating surface 8. Is formed to extend toward the tip end side in the axis O direction as it crosses the seat surface 8 at an obtuse angle and toward the tool rotation direction T, and a wall surface 10 that intersects the gauge surface 4 and the face surface 5 is formed. The wall surface 10 is inclined toward the outer peripheral side of the tool body 1 slightly toward the tool rotation direction T side and toward the rear end side in the axis O direction, and the first and second discharge grooves 9A. , 9B also open across the wall 10.

  On the other hand, a blow hole 11 extending toward the outer peripheral side of the tool main body 1 as it goes from the center of the bottom surface of the cylindrical portion (skirt portion) of the rear end portion toward the front end side in the axis O direction is formed in the front end portion of the tool main body 1 in the circumferential direction. In the present embodiment, three blow holes 11 are formed at equal intervals in the face surface 5 on the inner peripheral side of the tool body 1 in the gauge surface 4 of the third discharge groove 9C. Yes. Further, a communication groove 12 having a U-shaped cross section is formed between the opening on the face surface 5 of these blow holes 11 and the opening on the gauge surface 4 of the third discharge groove 9C opening on the outer peripheral side thereof. Has been.

  Furthermore, in this embodiment, the outer periphery of the rear end portion of the tool body 1 is also formed so as to have a diameter larger than that of the portion between the tip portion and the maximum outer portion of the expanded rear end portion. The diameter is set smaller than the diameter of the outer peripheral edge of the gauge surface 4 that is the maximum outer diameter of the tool body 1 described above. Further, the diameter-enlarged portion of the rear end portion of the tool body 1 has an axis O on the rear end side in the axis O direction of the rear end positions of the first to third discharge grooves 9A to 9C in the circumferential direction. Concave grooves 13 extending in parallel are formed.

  In the excavation tool configured as described above, the excavation tip 3 attached to the gauge surface 4 that is the outer peripheral portion of the distal end surface of the tool main body 1 has the tool main body 1 as its tip center line C moves toward the front end side in the axis O direction. Since it is inclined so as to go to the outer periphery side of the tool and to the tool rotation direction T side, the bending stress due to the rotational force in the tool rotation direction T is received as a compressive stress in the tip center line C direction, and relaxed. It is possible to prevent the chip 3 from being broken or the like.

  In this way, the tip center line C is inclined to the outer periphery side of the tool body 1 and the tool rotation direction T side, and the axial line O of the tool body 1 is in a torsional positional relationship. In the excavation tool, a planar seat surface 8 perpendicular to the tip center line C of the excavation tip 3 attached to the attachment portion 7 is formed adjacent to the attachment portion 7 of the excavation tip 3 on the gauge surface 4. When the excavation tip 3 is worn to some extent and is repolished, repolishing can be performed accurately by using the seating surface 8 as a reference. Specifically, instead of disposing the rotation axis of the regrinding wheel perpendicular to the chip center line C, repolishing may be performed by disposing the regrinding wheel parallel to the seating surface 8.

  Therefore, according to the excavation tool having the above-described configuration, it is possible to prevent the cutting edge of the excavation tip 3 from being re-polished due to distortion, and to ensure high fracture resistance to the cutting edge after re-polishing. For this reason, it is possible to perform stable excavation over a long period of time together with the fact that breakage or the like can be prevented from occurring in the excavation tip 3 due to the rotational force in the tool rotation direction T as described above. It is possible to provide a long-life drilling tool.

  In addition, in this embodiment, the excavation tip 3 attached to the gauge surface 4 on the outer peripheral portion of the tip surface of the tool body 1 has an outer peripheral edge of the gauge surface 4 which is a portion having the maximum outer diameter at the tip portion of the tool body 1. The gauge surface 4 is arranged so as to overlap in the direction of the axis O and to be positioned slightly further to the rear end side in the direction of the axis O than the outer peripheral edge. The excavation tip 3 excavates the outer peripheral edge of the gauge surface 4 that forms the maximum outer diameter of the tip of the tool body 1 in combination with the excavation tip 3 being arranged immediately on the tool rotation direction T side of the peripheral edge. It is possible to protect the tool body 1 from wear by protecting it with the excavation tip 3 itself from contact with the inner periphery of the excavation hole. Accordingly, it is possible to prevent the excavation tip 3 planted on the gauge surface 4 which is the maximum outer diameter portion from falling off early due to wear of the tool body 1 and to further extend the tool life. .

  Further, in the present embodiment, the seat surface 8 is formed adjacent to at least the tool rotation direction T side of the attachment portion 7 in the gauge surface 4 of the outer peripheral portion of the tip surface of the tool body 1. Here, the tip center line C of the excavation tip 3 attached to the attachment portion 7 of the gauge surface 4 is inclined to the outer peripheral side of the tool body 1 and the tool rotation direction T side as it goes to the front end side in the axis O direction as described above. Therefore, the seating surface 8 perpendicular to the tip center line C is inclined toward the rear end side in the axis O direction from the mounting portion 7 toward the outer peripheral side of the tool body 1 and the tool rotation direction T side. A large space is secured on the tool rotation direction T side and the outer peripheral side of the excavation tip 3 as compared with the case where the conical gage surface 4 is left as it is.

  For this reason, according to the present embodiment, the flour generated by the excavation tip 3 attached to the gauge surface 4 is pushed out by the excavation tip 3 by the rotation of the tool body 1 and the tool rotation direction T side and the outer peripheral side described above. Efficient discharge from space. Therefore, it is possible to prevent such dusting from staying on the seating surface 8, and it is possible to prevent a situation in which the tool body 1 is worn by the dusting and the excavation tip 3 is removed early.

  Furthermore, in the present embodiment, discharge grooves 9 are formed on the outer periphery of the distal end portion of the tool body 1 whose diameter has been expanded, and these discharge grooves 9 are formed in the tool rotation direction of the mounting portion 7 on the gauge surface 4 as described above. It opens to the seating surface 8 formed adjacent to the T side. For this reason, in particular, the dust that is pushed out in the tool rotation direction T by the cutting edge of the excavation tip 3 can be discharged from the discharge groove 9 to the rear end side of the tool body 1, and the tool body 1 is worn by the dusting. Can be more reliably prevented.

  In addition, in this embodiment, the discharge grooves 9 of these dusts are inclined so as to go to the opposite side of the tool rotation direction T toward the rear end side in the axis O direction. The powder is pushed out to the rear end side of the tool body 1, and further passes through a concave groove 13 formed in the rear end portion of the tool body 1 whose diameter has been further expanded, between the excavation rod and the excavation hole on the rear end side of the tool body 1. Discharged into the space. Therefore, the flour discharged from the seat surface 8 to the discharge groove 9 can be quickly removed from between the tool body 1 and the excavation hole, and the resistance during excavation can be reduced.

  Moreover, the direction of the inclination of the discharge grooves 9 is the same as the direction of the inclination of the tip center line C of the excavation tip 3 attached to the attachment portion 7 formed on the gauge surface 4 as described above. For this reason, the wall thickness of the tool body 1 between the mounting portion 7 formed as a concave hole and the discharge groove 9 adjacent in the circumferential direction can be made relatively uniform, and the flow flowing through the discharge groove 9 can be made uniform. It is possible to prevent the excavation tip 3 from dropping off early due to abrasion due to powder.

  Of these discharge grooves 9, the third discharge groove 9 </ b> C having a deep groove length and a long groove length is connected to the blow hole 11 formed at the tip of the tool body 1, and the communication groove 12 on the face surface 5. It communicates through. And at the time of excavation, the compressed air supplied through the excavation rod is ejected from the blow hole 11 to the communication groove 12, so that the flour discharged in the third discharge groove 9C can be pushed out to the rear end side. According to this embodiment, it is possible to more efficiently discharge the flour.

  In this embodiment, the case where a button tip having a hemispherical cutting edge is used as the excavating tip 3 has been described. However, a ballistic drilling tip having a bullet-shaped cutting edge or a rear end portion of the cutting edge is a truncated cone. It is of course possible to apply the present invention to a drilling tool in which a spike type drilling tip having a shape and a hemispherical tip having a small radius is mounted on the mounting portions 6 and 7. In addition, the excavation tip 3 attached to the attachment portion 6 of the face surface 5 is also in the tool rotation direction T side as the tip center line C moves toward the front end side in the axis O direction, as in the excavation tool described in Patent Document 1. It may be inclined.

DESCRIPTION OF SYMBOLS 1 Tool main body 2 Female thread part 3 Excavation tip 4 Gauge surface (outer peripheral part of the front end surface of the tool main body 1)
5 Face surface 6, 7 Mounting portion 8 Seat surface 9 (9A to 9C) Discharge groove 10 Wall surface 11 Blow hole 12 Communication groove 13 Concave groove O Tool body 1 axis T Tool rotation direction C Tip center line

Claims (3)

The outer peripheral part of the tip surface of the tool body rotated around the axis is a conical gauge surface centered on the axis that is reduced in diameter toward the tip side of the tool body. The inner peripheral portion of the distal end surface on the peripheral side is a flat face surface perpendicular to the axis, and excavation tips are attached to the gauge surface and the face surface ,
The excavation tip attached to the gauge surface is inclined so that the tip center line is directed toward the outer peripheral side of the tool body and the tool rotation direction side as it goes toward the tip end side in the axial direction.
A planar seating surface perpendicular to the tip center line is formed on the gauge surface , which is the outer peripheral portion of the tip surface of the tool body, adjacent to at least the tool rotation direction side of the attachment portion of the excavation tip. And
The seating surface is inclined toward the rear end side in the axial direction as it goes from the mounting portion toward the outer peripheral side of the tool body and the tool rotating direction side, and the outer peripheral portion of the face surface is partially formed on the tool rotating direction side. An excavation tool which extends so as to be cut out and intersects with the outer peripheral edge of the gauge surface . The excavation tool according to claim 1 , wherein a discharge groove for dusting that opens to the seat surface is formed on an outer peripheral portion of the tool body on a tool rotation direction side of the excavation tip mounting portion. The excavation chips, tool according to claim 1 or claim 2, characterized in that overlap in part with the axis direction forming an maximum outer diameter at the tip of the tool body.

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