JP2022114685A - Excavation chip and excavation tool - Google Patents

Abstract

To suppress progress of abrasion of a tip part in a chip body of an excavation chip so as to suppress a decline in excavating efficiency and to reduce cost in re-polishing process.SOLUTION: An excavation chip is rotated along an axis line and gives striking power and is attached to a tip surface of tool body. The excavation chip comprises a chip body in which a columnar base end part and a tip part projecting from the base end part to the tip side are integrally formed. The tip part has a convex surface shape part projecting to the tip side of the chip body and a protrusion part which extends in the extension direction along the diameter direction with respect to a center line of the base end part when looking from the tip side of the chip body and which protrudes from the surface of the convex surface shape part to the tip side. The protrusion part has a thickest part with the largest projection height from the convex surface shape part and the summit of the thickest part is eccentrically arranged on one side of the extension direction from the center line.SELECTED DRAWING: Figure 1

Description

The present invention relates to drilling tips and drilling tools.

In excavating tools that are rotated around the axis and are used for drilling by applying impact energy output from a rock drilling device such as a top hammer or a down-the-hole hammer to the tool body that is rotated around the axis, the tip surface of the tool body is A hard drilling tip called a button bit (button bit) is attached to the rocker, and drilling is performed by bringing the tip of the drilling tip into contact with the bedrock and propagating impact energy.

As the drilling tip attached to the tip surface of the tool body of the drilling tool, there are a button tip with a hemispherical tip, a ballistic tip with a bullet-shaped tip, or a conical tip with a rounded tip. Spike tips are known, and the optimum shape is selected depending on the rock type, but if the tip of the tip body is significantly worn due to the drilling process, the button tip is generally selected. .

As the drilling progresses, the drilling tip wears at the tip of the tip body, resulting in a decrease in drilling efficiency and reaching the end of its life. In addition, a drilling tip with a worn tip body is reused by regrinding the tip to regenerate the cutting edge shape. As the drilling tip (gauge tip) attached to the surface wears down, the diameter of the drilled hole becomes smaller. For this reason, in order to maintain the drilling efficiency over a long period of time, it is necessary to make the shape of the tip portion of the tip body resistant to wear.

Patent Document 1 describes a cylindrical mounting portion in which a blade body (chip body) of a carbide tip (drilling tip) is embedded in a base metal (tool body), and a perforation formed at the upper end of the mounting portion. The drilling tip is formed in a shape in which a plurality of hemispheres with a radius of at least 1 mm or more are stacked while the curvature radius gradually decreases toward the tip side.

Similarly, in Patent Document 2, for the purpose of maintaining the drilling efficiency over a long period of time, the tip of the gauge tip has a cross section along the tip center line with a stepped curvature radius toward the tip side. A drilling tip is described which is formed with at least two stepped convex curved surface portions forming a convex curved surface that becomes smaller.

JP-A-7-293173 JP 2012-057310 A

The wear of the drilling tip is caused by the top part of the tip body that most protrudes toward the tip side of the tool body (the intersection of the center line of the cylindrical base end of the tip body and the tip surface), which comes into strong contact with the bedrock. , and spreads like a band in the radial direction to the center line when viewed from the tip side of the tip body to the portion extending in the radial direction to the axis of the tool body from this portion. In particular, since the gauge tip described above has a long rolling distance due to the rotation of the tool body for drilling and has many parts that wear due to contact with the object to be drilled, such band-like wear becomes even more pronounced.

The present invention has been made under such a background, and a drilling tip capable of suppressing the deterioration of drilling efficiency by suppressing the progress of wear of the tip and reducing the cost of regrinding. The purpose is to provide drilling tools.

A drilling tip according to one aspect of the present invention is a drilling tip attached to a tip surface of a tool body that is rotated about an axis and applied with an impact force, and has a columnar base end and a tip end side from the base end. A tip body integrally formed with a protruding tip portion is provided, and the tip portion includes a convex curved portion protruding toward the tip side of the tip body and a portion of the base end portion when viewed from the tip side of the tip body. a ridge that extends in a direction extending diametrically with respect to the center line and protrudes from the surface of the convex curved portion toward the tip side, wherein the ridge has a protrusion height from the convex curved portion. The thickest portion has a maximum thickness, and the vertex of the thickest portion is arranged to be biased from the center line to one end side in the extending direction.

According to this configuration, the tip portion of the tip body is provided with the ridge portion that protrudes further to the tip side from the surface of the convex curved portion. Therefore, by attaching the excavating tip so that the ridge portion extends in the radial direction with respect to the axis when viewed from the tip side of the tool body, the wear of the tip portion of the tip body progressing in a band shape in the radial direction with respect to the axis can be reduced. can be limited to Therefore, it is possible to extend the life of the tip body, and to suppress the deterioration of the drilling efficiency of the drilling tool. Moreover, when the drilling tip is to be regrinded, it is only necessary to regrind the ridge portion without regrinding the entire tip portion. Economical regrinding can be performed.

Further, generally, the wear of the drilling tip tends to be greater in a region distant from the axis of the tool body. Therefore, the drilling tip wears more conspicuously, disproportionately radially outwardly of the tool. According to the above configuration, the apex of the thickest portion of the ridge portion is arranged to be biased toward one end side in the extending direction from the center line. Further, the excavating tip having the above-described configuration is attached to the tool body so that one end side in the extending direction where the apex is arranged with deviation is arranged radially outside of the axis of the tool body. According to the above-described configuration, since the area where wear is likely to progress is formed thick in advance, the shape of the protrusion can be maintained even if the wear progresses, and a decrease in drilling efficiency can be suppressed.

In the above-described excavation tip, the height of protrusion of the ridge portion from the convex curved portion is the smallest at both ends in the extending direction, and as it goes from the both ends in the extending direction to the thickest portion. A configuration in which the protrusion height from the convex curved portion gradually increases may be employed.

According to this configuration, the projection height of the ridge gradually decreases from the thickest portion toward both ends in the extending direction. Since the amount of wear of the protrusion gradually decreases from the thickest portion toward both ends in the extending direction, the protrusion height is appropriately ensured according to the amount of wear. As a result, the drilling tip can maintain the shape of the tip even when the ridge portion is worn out, and stable drilling can be performed.

In the above-described digging tip, the angle formed by the protruding direction of the thickest portion and the center line may be 0° or more and 45° or less.

According to this configuration, the shape of the protrusion can be sufficiently maintained against progress of wear of the protrusion.

In the above-described digging tip, the protruding height of the thickest portion of the ridge from the convex curved portion is 1.0 times the height of protrusion from the convex curved portion on the center line. It is good also as a structure which is more than 1.5 times or less.

According to this configuration, the shape of the protrusion can be sufficiently maintained against progress of wear of the protrusion.

In the above-described digging tip, the width dimension of the ridge portion may be configured to gradually decrease from the surface of the convex curved portion toward the tip side in the projecting direction.

According to this configuration, it is possible to ensure the strength of the ridge portion and to ensure a large regrinding margin.

In the above-described excavation tip, both end portions of the ridge portion in the extending direction may be positioned at a boundary portion between the base end portion and the tip end portion.

According to this configuration, since the protrusion is formed over the entire length of the tip portion in the extending direction, wear of the tip portion can be suppressed more reliably.

In the above-described excavation tip, the maximum value of the width dimension of the root portion of the ridge portion connected to the convex curved portion is in the range of 1/3 or more and 3/4 or less of the diameter D of the base end portion. may be

If the maximum width dimension is less than 1/3 of the diameter of the proximal end, it may not be possible to reliably suppress wear at the tip, whereas if it exceeds 3/4, resistance may increase. be.

In the above-described digging tip, the convex curved portion may have a hemispherical shape centered on the center line.

According to this configuration, by forming the convex curved portion in a hemispherical shape like a button tip, it is possible to suppress wear of the tip portion of the tip body to some extent even if the ridge portion is worn out.

In the above-described digging tip, the convex curved portion may have a cannonball shape centered on the center line.

By forming the projecting portion into a cannonball shape, it is possible to increase the excavation efficiency and the excavation speed by the excavation tip as compared with the hemispherical shape. Further, as described above, since the ridge portion of the excavation tip has the thickest portion, the excavation efficiency can be maintained even if the wear progresses. That is, according to this configuration, it is possible to increase the excavation efficiency of the excavation tip and prevent the excavation efficiency from being lowered even if the excavation proceeds.

In the above-described excavation tip, the protrusion height of the ridge portion at the thickest portion from the convex curved portion is within a range of 9/100 or more and 30/100 or less of the diameter of the base end portion. may be configured.

By setting the protruding height of the thickest portion to 9/100 or more of the diameter of the base end portion, the excavating tip can be used for a sufficiently long time even when the ridge portion is worn. On the other hand, by setting the protruding height of the thickest portion to 30/100 or less of the diameter of the base end portion, it is possible to sufficiently secure the rigidity of the thickest portion and sufficiently improve the drilling efficiency.

In the above-described drilling tip, the ridge may be formed of a polycrystalline diamond sintered body.

In the drilling tip described above, wear of the tip of the tip body is limited to the ridge. By forming the ridges from a polycrystalline diamond sintered body having a higher hardness than cemented carbide, which is usually used as a material for the tip body, wear of the tip body can be further suppressed and the life can be extended. . In addition, by making only the ridge part of the polycrystalline diamond sintered body, the entire tip of the tip body made of cemented carbide can be made multiplied like a general drilling tip using a polycrystalline diamond sintered body. It is also more economical than coating with a crystal diamond sintered body.

In the above-described excavation tip, the protrusion may have a widened portion whose width increases toward one side in the extending direction.

According to this configuration, it is possible to suppress the local progress of wear in the area where the progress of wear is likely to progress. As a result, even when the drilling tip is used for a long period of time, the shape of the ridge portion can be maintained, and a decrease in drilling efficiency can be suppressed.

A digging tool according to one aspect of the present invention includes the above-described digging tip, and a tool body that holds the digging tip on a tip surface and is rotated around an axis, and the digging tip has the tip part that is the tip end. The extending direction of the ridge portion is aligned with the radial direction with respect to the axis of the tool body, and one end side of the extending direction where the vertices are arranged to be biased is aligned with the axis. Placed radially outward.

According to this configuration, the drilling tip is attached to the tool body so that the one end side in the extending direction where the apex of the thickest portion is biased is arranged radially outside of the axis of the tool body. As a result, it is possible to fully enjoy the effects of using the above-described digging tip.

According to the present invention, it is possible to suppress the progress of wear of the tip portion of the tip body of the drilling tip, suppress the deterioration of the drilling efficiency of the drilling tool, and even when performing re-grinding, Since it is only necessary to regrind the ridges, the cost required for regrinding can be reduced, and efficient and economical drilling can be performed.

1 is a perspective view of one embodiment of a drilling tip; FIG. FIG. 2 is a front view of one embodiment of a drilling tip. 3 is a first side view of one embodiment of a drilling tip; FIG. 4 is a second side view of an embodiment drilling tip; FIG. FIG. 5 is a front view of an embodiment drilling tool. FIG. 6 is a side view of an embodiment drilling tool. FIG. 7 is a front view of a drilling tip (button tip) of conventional construction. FIG. 8 is a first side view of a conventionally constructed drilling tip (button tip). FIG. 9 is a second side view of a conventionally constructed drilling tip (button tip). FIG. 10 is a front view showing a worn state of a drilling tip (button tip) having a conventional structure. FIG. 11 is a first side view showing the state of wear of a conventional drilling tip (button tip). FIG. 12 is a second side view showing the state of wear of the conventional drilling tip (button tip). FIG. 13 is a front view showing a worn state of the drilling tip of one embodiment. FIG. 14 is a first side view showing a worn state of the drilling tip of one embodiment. FIG. 15 is a second side view showing the wear condition of the drilling tip of one embodiment. FIG. 16 is a schematic diagram showing a regrinding process for a drilling tip (button tip) having a conventional structure. FIG. 17 is a schematic diagram showing a regrinding step of the drilling tip of one embodiment. 18 is a plan view of a drilling tip of Modification 1. FIG. 19 is a side view of a drilling tip of modification 2. FIG.

Embodiments to which the present invention is applied will be described in detail below with reference to the drawings.
1-4 illustrate a drilling tip 10 of one embodiment. 5 and 6 show a drilling tool 20 of the present invention with a drilling tip 10 attached.

1 to 4 illustrate the Z-axis extending along a centerline C, which will be described later. In each figure, the tip side of the excavation tip 10 or tip body 1 is the +Z side, and the base side is the -Z side.

In the following description, the direction along the centerline C may be simply referred to as the "axial direction". The axial direction is synonymous with the Z-axis direction. In addition, since the drilling tip 21 may be tilted and fixed with respect to the axis O of the drilling tool 20 to be described later, the axial direction of the center line C is not necessarily the axial direction of the axis O of the drilling tool 20. It does not match.

As shown in FIGS. 5 and 6, the drilling tip 10 is attached to the tip surface 12 of the tool body 11. As shown in FIGS. The excavation tip 10 is attached to the tool body 11 with the tip side facing the object to be excavated. The tool body 11 is rotated around the axis O and is given an impact force.

As shown in FIGS. 1-4, the drilling tip 10 comprises a tip body 1 . The tip body 1 is made of hard material such as cemented carbide. The tip body 1 has a proximal end portion 2 and a distal end portion 3 integrally formed.

The base end portion 2 has a cylindrical shape centered on the center line C. As shown in FIG. The rear end surface of the base end portion 2 is formed in a truncated cone shape whose diameter decreases toward the rear end side of the tip body 1 .

As long as the base end portion 2 is a columnar shape extending in one direction with a uniform cross-sectional shape, the base end portion 2 may be a columnar shape having a different cross-sectional shape, such as a polygonal column or an elliptical column. If the proximal end has a cross-sectional shape other than circular, the straight line connecting the centers of gravity of the cross-sections becomes the center line of the proximal end.

The distal end portion 3 protrudes from the proximal end portion 2 to the distal side. The tip portion 3 has a convex portion 4 and a ridge portion 5 . The convex curved portion 4 of this embodiment has a hemispherical shape centered on the center line C. As shown in FIG. The convex curved portion 4 protrudes toward the tip of the tip body 1 .

In this embodiment, the case where the convex curved portion 4 is hemispherical is exemplified, but the curved surface shape of the convex curved portion 4 may be another convex curved surface. For example, the convex curved portion may be elliptical, cannonball-shaped, or the like.

The ridge portion 5 protrudes from the surface of the convex curved portion 4 to the tip side. The ridge portion 5 extends linearly in the extending direction. The extending direction of the ridge portion 5 is along the diametrical direction with respect to the center line C of the base end portion 2 when viewed from the tip side of the tip body 1 .

As shown in FIG. 4 , the projection height of the ridge portion 5 from the convex curved portion 4 changes along the extending direction. Here, the projection height of the ridge portion 5 means the height dimension along the normal direction of the ridge portion 4 from the surface of the ridge portion 4 to the tip of the ridge portion 5 . In the following description, the normal direction of the surface of the convex curved portion 4 from which the ridge portion 5 protrudes will be referred to as the projection direction of the ridge portion 5 . That is, the height of protrusion from the convex curved portion 4 means the height dimension of the protrusion 5 in the direction of protrusion.

The ridge portion 5 has a thickest portion 6 having the largest protrusion height from the convex curved portion 4 . The thickest portion 6 has a vertex 6p. The vertex 6p is the tip of the thickest portion 6 in the direction in which it protrudes. A vertex 6p of the thickest portion 6 is arranged so as to deviate from the center line C toward one end side in the extending direction.

The projection height from the convex curved portion 4 is the smallest at both end portions in the extending direction of the ridge portion 5 . The protruding portion 5 gradually increases in height from the convex curved portion 4 toward the thickest portion 6 from both ends in the extending direction. Both ends of the protrusion 5 in the extending direction are located at the boundary between the base end 2 and the tip end 3 . That is, the ridge portion 5 of the present embodiment is provided over the entire diametrical region of the distal end portion 3 when viewed from the distal end side. Fillet portions that are smoothly connected to the base end portion 2 may be provided at both end portions in the extending direction of the ridge portion 5 .

As shown in FIG. 3, the width dimension of the protrusion 5 gradually decreases from the surface of the convex curved portion 4 toward the tip side in the projecting direction. Here, the width dimension of the ridge portion 5 means the dimension of the ridge portion 5 in the direction orthogonal to the extending direction of the ridge portion 5 when viewed from the axial direction. The width direction, which serves as a reference for the width dimension, is the direction perpendicular to the extension direction when viewed from the axial direction.

As shown in FIG. 2 , the width dimension of the root portion of the ridge portion 5 connected to the convex curved portion 4 gradually increases from both ends in the extending direction toward the thickest portion 6 . On the other hand, the width dimension of the tip portion (the top surface 5b described later) of the ridge portion 5 is substantially uniform along the vertical direction.

It is preferable that the maximum value W of the width dimension at the root portion of the ridge portion 5 connected to the convex curved portion 4 is within the range of 1/3 or more and 3/4 or less of the diameter D of the base end portion 2. More preferably, it is in the range of 1/3 or more and 1/2 or less. In this embodiment, the maximum value W of the width dimension is located at the base of the thickest portion 6 of the ridge portion 5 .

As shown in FIG. 3, the surface of the ridge portion 5 is provided with two inclined surfaces 5a facing both sides in the width direction and a top surface 5b connecting the tops of the two inclined surfaces 5a. An intersection ridgeline portion between the two inclined surfaces 5a and the top surface 5b is chamfered by a convex curved surface. A corner portion where the two inclined surfaces 5a and the convex curved portion 4 intersect is a concave curved surface.

The top surface 5b has a convex curved shape with a radius of curvature equal to the radius of curvature of the convex curved portion 4 when viewed from the extending direction. Note that the top surface 5b may be a surface formed in a straight line when viewed from the extending direction. The apex 6p of the thickest portion 6 described above is arranged on the top surface 5b.

The inclined surface 5a has a convex curved shape that slightly bulges outward in the width direction when viewed from the extending direction. The two inclined surfaces 5a are inclined so as to approach each other from the convex curved portion 4 toward the distal end side of the ridge portion 5. As shown in FIG. That is, the protrusion 5 protrudes in an isosceles trapezoidal shape when viewed from the extending direction.
Note that the inclined surface 5a may be a surface formed in a straight line when viewed from the extending direction. Further, the inclined surface 5a may have a concave surface shape that is concave inward in the radial direction when viewed from the extending direction.

As shown in FIGS. 5 and 6, the drilling tip 10 is attached to the tip surface 12 of the tool body 11 that is rotated around the axis O. As shown in FIGS. A plurality of digging tips 10 and the tool body 11 constitute a digging tool 20 . That is, the drilling tool 20 has a plurality of drilling tips 10 and a tool body 11 that holds the plurality of drilling tips 10 . The drilling tool 20 is used for drilling a rock or the like.

The tool body 11 is made of a metal material such as steel. The tool body 11 has a multi-stage cylindrical shape centered on the axis O. As shown in FIG. A rear end portion of the tool body 11 is provided with a shank portion 13 attached to a down-the-hole hammer (not shown). A head portion 14 having a larger diameter than the shank portion 13 is provided at the tip portion of the tool body 11 .

The head portion 14 has a substantially circular shape when viewed from the axial direction of the axis O. As shown in FIG. The head portion 14 has a tip surface 12 facing the tip side of the tool body 11 . The tip surface 12 has a face surface 12a and a gauge surface 12b. Drilling tip 10 is attached to both face surface 12a and gauge surface 12b. That is, the tool body 11 holds the excavation tip 10 on the tip surface 12 .

In this embodiment, the drilling tip 10 is attached to both the face surface 12a and the gauge surface 12b. However, the drilling tip 10 may be attached to only one of the face surface 12a and the gauge surface 12b. Alternatively, the digging tip 10 of the present embodiment may be attached only to the gauge surface 12b, and a digging tip (for example, a button tip) having a conventional structure may be attached to the face surface 12a.

The face surface 12a is located in the center of the tool body 11 around the axis O. As shown in FIG. The face surface 12a has a substantially circular shape centered on the axis O when viewed from the axial direction of the axis O. As shown in FIG. The face surface 12a includes an annular flat surface perpendicular to the axis O, and a mortar-shaped tapered surface located radially inside the flat surface and inclined toward the rear end side of the tool body 11 toward the inner peripheral side. and have

The gauge surface 12b has a circular shape centered on the axis O when viewed in the axial direction of the axis O. As shown in FIG. The gauge surface 12b is arranged on the outer circumference of the face surface 12a. When viewed from the axial direction of the axis O, the gauge surface 12b surrounds the face surface 12a from the outside in the radial direction. The gauge surface 12b is a tapered surface extending toward the rear end side of the tool body 11 as it goes radially outward of the axis O. As shown in FIG.

A plurality of blow holes 16 are opened in the face surface 12 a of the head portion 14 . The blow hole 16 extends along the axis O from the rear end surface of the shank portion 13 . Further, the face surface 12 a is provided with a groove portion 17 connecting the opening of the blow hole 16 to the discharge groove 15 .

A plurality (eight in the present embodiment) of discharge grooves 15 extending parallel to the axis O are provided on the outer peripheral surface of the head portion 14 . The grinding powder generated in the drilling process is discharged to the rear of the head portion 14 through the discharge groove 15 together with the blow discharged from the blow hole 16 .

The face surface 12a and the gauge surface 12b are provided with a plurality of holes 12h having circular cross sections. The hole 12h extends perpendicular to the face surface 12a and the gauge surface 12b where it is provided. The base end portion 2 of the drilling tip 10 is fitted into the hole portion 12h by tight fitting such as shrink fitting or press fitting.

Centerline C of drilling tip 10 is disposed perpendicular to face surface 12a and gauge surface 12b. The digging tip 10 is attached with the tip portion 3 protruding from the tip surface 12 (the face surface 12a and the gauge surface 12b).

The drilling tip 10 is attached so that the extending direction of the ridge portion 5 is aligned with the radial direction of the axis O of the tool body 11 . That is, in the excavation tip 10 attached to the excavation tool 20, the extending direction of the ridge portion 5 extends in the radial direction with respect to the axis O when viewed from the tip side. At this time, one end side in the extending direction where the vertex 6p of the protrusion 5 is arranged is arranged radially outside of the axis O. As shown in FIG.

The extension direction of the ridge portion 5 of the excavation tip 10 is allowed to deviate slightly from the radial direction of the axis O within the range resulting from an assembly error at the time of attachment. More specifically, even if the extending direction of the ridge portion 5 deviates from the radial direction of the axis O within a range of ±10°, a sufficient effect can be obtained.

The drilling tool 20 is rotated in the tool rotation direction T around the axis O by a rotary drive device connected to the down-the-hole hammer via a drilling rod (not shown). Furthermore, the drilling tool 20 is given an impact force from the down-the-hole hammer to the tip side in the direction of the axis O. As a result, the excavating tool 20 excavates by crushing the bedrock with the excavating tip 10 attached to the tip surface 12 of the tool body 11 .

7 to 9 show a state in which a button tip, which is a digging tip 21 having a conventional structure, is attached to the tool body 22. FIG. 10 to 12 specifically show progress of wear of the drilling tip 21 having a conventional structure. In FIGS. 10 to 12, portions where wear progresses are highlighted by shading.

As shown in FIGS. 10 to 12, in the drilling tip 21 having the conventional structure, when the drilling process is performed, the wear of the tip progresses in a band shape in the radial direction with respect to the axis of the tool body 22 . As the wear progresses in a belt-like manner, the excavation tip 21 becomes flat at the contact portion with respect to the excavation object, and cannot apply a local impact force to the excavation object. As a result, the drilling tip 21 having the conventional structure has a problem of reduced drilling efficiency.

It should be noted that, as shown in FIG. 12 , the wear of the excavating tip 21 is greatest in a region away from the axis O of the excavating tool 20 with respect to the center line C of the excavating tip 10 . Therefore, the amount of wear of the drilling tip 21 is not symmetrical with respect to the center line C. This is because the rolling distance due to the rotation of the tool body 11 around the axis O is long in the region far from the axis O, and the contact with the excavation object tends to wear the area.

13 to 15 show the state where the drilling tip 10 of this embodiment is attached to the tool body 11. FIG. In FIGS. 13 to 15, progress of wear is emphasized by shading.

The distal end portion 3 of the excavation tip 10 of the present embodiment is provided with a ridge portion 5 extending in a radial direction with respect to the axis O of the excavation tool 20 . That is, the drilling tip 10 has a thickened region in advance, which is likely to be worn during the drilling process. As a result, even if wear progresses, only the ridges 5 can contact the object to be excavated, giving a local impact to the object to be excavated, and suppressing a decrease in drilling efficiency. That is, according to this embodiment, the life of the drilling tip 10 can be extended.

Among the plurality of excavation tips 10, those attached to the gauge surface 12b have a long rolling distance due to the rotation of the excavation tool 20 around the axis O, and have many parts that are worn by contact with the excavation target. Although such band-like wear is more pronounced, the life of the drilling tip 10 mounted on such a gauge face 12b can also be extended.

As described above, according to the drilling tip 10 of the present embodiment, the apex 6p of the thickest portion 6 of the ridge portion 5 is arranged to deviate from the center line C toward one end side in the extending direction. As shown in FIG. 15 , the drilling tip 10 is attached to the tool body 11 so that one end side in the extending direction where the apex 6p is biased is arranged radially outward of the axis O. As shown in FIG. As a result, the thickest portion 6 is arranged radially outward of the axis O in a state where the excavating tip 10 is attached to the tool body 11 .

As described with reference to FIG. 12 , the excavation tip 10 is disproportionately radially outward of the axis O and significantly worn. As shown in FIG. 15, according to the present embodiment, the thickest portion 6 is arranged radially outward of the axis O. As shown in FIG. As a result, the area where wear tends to progress is formed thick in advance, and the shape of the protrusion 5 can be maintained even if the wear progresses. As a result, even if wear progresses, it is possible to suppress a decrease in drilling efficiency. That is, according to this embodiment, the life of the tip body 1 can be further extended.

As shown in FIG. 4, in the present embodiment, it is preferable that the angle .alpha. By setting the angle α to 0° or more and 45° or less, the shape of the protrusion 5 can be sufficiently maintained against the progression of wear of the protrusion 5 . Further, in the present embodiment, the protrusion height hp at the thickest portion 6 of the ridge portion 5 from the convex curved portion 4 is greater than the protrusion height hc from the convex curved portion 4 on the center line C. It is 1.0 times or more and 1.5 times or less. By setting the height of the thickest portion 6 in this manner, the shape of the protrusion 5 can be sufficiently maintained against the progression of wear of the protrusion 5 .

According to this embodiment, the projecting height of the ridge portion 5 from the convex curved portion 4 is the smallest at both end portions in the extending direction. Moreover, the protrusion height from the convex curved portion 4 gradually increases as the protrusion 5 extends from both ends in the extending direction toward the thickest portion 6 . That is, the projection height of the ridge portion 5 gradually decreases from the thickest portion 6 toward both end portions in the extending direction. Since the amount of wear of the protrusion 5 gradually decreases from the thickest portion 6 toward both end portions in the extending direction, the protrusion height is appropriately secured according to the amount of wear. As a result, the excavation tip 10 can maintain the shape of the tip even when the wear of the protrusion 5 progresses, thereby suppressing a decrease in drilling efficiency.

According to this embodiment, the width dimension of the ridge portion 5 gradually decreases from the surface of the convex curved portion 4 toward the distal end side in the projecting direction. As a result, the strength of the ridge portion 5 can be secured, and a large regrinding margin can be secured, which is much more efficient and economical.

According to the present embodiment, both end portions in the extending direction of the ridge portion 5 are positioned at the boundary portion between the base end portion 2 and the tip end portion 3 . That is, the ridge portion 5 is formed over the entire diameter of the distal end portion 3 . For this reason, compared with the case where the protrusion 5 is partially provided over the entire diametrical area of the tip portion 3 , it is possible to more reliably suppress wear of the tip portion 3 of the tip body 1 .

In the present embodiment, the maximum value W of the width dimension of the root portion of the ridge portion 5 connected to the convex curved portion 4 is within the range of 1/3 or more and 3/4 or less of the diameter D of the base end portion 2. is preferred. If the maximum value W of the width dimension is less than 1/3 of the diameter D of the base end portion 2, the width of the top surface 5b of the projection portion 5 is also reduced, so that the wear of the tip portion 3 can be reliably suppressed. may disappear. On the other hand, if the maximum value W of the width dimension exceeds 3/4 of the diameter D of the base end portion 2, the width of the top surface 5b becomes too large, which may lead to an increase in resistance due to contact with the bedrock. . Therefore, by setting the maximum value W within the range of 1/3 or more and 3/4 or less of the diameter D, it is possible to reduce the resistance during excavation while suppressing wear of the ridges 5 . Furthermore, by setting the maximum value W within the range of 1/3 or more and 1/2 or less of the diameter D, this effect can be obtained more remarkably.

In the present embodiment, the width dimension of the root portion of the ridge portion 5 connected to the convex curved portion 4 increases from both ends in the extending direction toward the thickest portion 6 . As a result, the strength of the ridges 5 at the thickest portion 6 can be secured, and when the thickest portion 6 is worn and the thickest portion 6 is to be regrinded, the regrinding margin is increased. can be secured.

In this embodiment, the convex curved portion 4 has a hemispherical shape centered on the center line C. As shown in FIG. Therefore, by forming the convex curved portion 4 into a hemispherical shape like a button tip, it is possible to suppress abrasion of the tip portion 3 of the tip body 1 even if the ridge portion 5 is worn out.

In this embodiment, the projection height of the ridge 5 at the thickest portion 6 from the convex curved surface portion 4 is within a range of 9/100 or more and 30/100 or less of the diameter of the base end portion 2. is preferred. By setting the protruding height of the thickest portion 6 to 9/100 or more of the diameter of the base end portion 2, the excavation tip 10 can be used for a sufficiently long time even when the ridge portion 5 is worn. can. On the other hand, by setting the protruding height of the thickest portion 6 to be 30/100 or less of the diameter of the base end portion, the rigidity of the thickest portion 6 can be sufficiently secured, and the drilling efficiency can be sufficiently improved.

In this embodiment, the ridge portion 5 may be formed of a polycrystalline diamond sintered body. In the digging tip 10 of this embodiment, the wear of the tip portion 3 of the tip body 1 is limited to the ridge portion 5 . Therefore, by forming the ridges 5 from a polycrystalline diamond sintered body having a higher hardness than the cemented carbide normally used for the tip body 1, wear of the tip body 1 is further suppressed and the life is extended. can do. In addition, it is more economical than a general drilling tip using a polycrystalline diamond sintered body, in which the entire tip of the tip body made of cemented carbide is covered with a polycrystalline diamond sintered body. .

Further, in a general drilling tip using a polycrystalline diamond sintered body, the entire surface of the tip portion of the tip body made of cemented carbide is covered with the polycrystalline diamond sintered body. In this case, a large amount of polycrystalline diamond sintered body may be required depending on the thickness of the coating layer of the polycrystalline diamond sintered body. In contrast, as shown in the present embodiment, when the polycrystalline diamond sintered body is formed only on the protrusion 5, the amount of the polycrystalline diamond sintered body used can be suppressed, which is economical. be.

16 and 17 are schematic diagrams showing the regrinding process of the drilling tip. FIG. 16 shows a regrinding process for the button tip, which is the drilling tip 21 of conventional structure, and FIG. 17 shows a regrinding process for the drilling tip 10 of the present embodiment.

The cup-shaped grindstone 24 has a concave spherical diamond abrasive grain layer 23 . As shown in FIGS. 16 and 17, the regrinding step is carried out by housing the drilling tip to be ground in the concave spherical diamond abrasive grain layer 23 of the cup-shaped grindstone 24 and rotating it.

The conventionally structured drilling tip 21 wears in a belt-like manner. For this reason, when regrinding the drilling tip 21 having the conventional structure, the entire tip must be ground in order to adjust the shape of the tip, which increases the cost and time required for regrinding.

On the other hand, in the drilling tip 10 of the present embodiment, the ridges 5 are concentrated and worn. Moreover, the protrusion 5 protrudes at the tip portion 3 . As shown in FIG. 17, in the regrinding step of the drilling tip 10 of the present embodiment, only the ridge 5 is ground in contact with the diamond abrasive grain layer 23, and the entire tip 3 needs to be regrinded. do not have. Therefore, the cost and time required for regrinding can be reduced, and the consumption of the cup-shaped grindstone 24 can be minimized, so that regrinding can be performed efficiently and economically.

The shape of the inner surface of the cup-shaped grindstone 24 for regrinding the drilling tip 10 is preferably a shape suitable for grinding the thickest portion 6 . As a result, even in the drilling tip 10 after regrinding, it is possible to achieve a configuration in which the ridge portion 5 is arranged biased from the center line C toward one end side in the extending direction.

(Modification 1)
FIG. 18 is a plan view of a drilling tip 110 of Modification 1 that can be employed in this embodiment. In addition, the same code|symbol is attached|subjected about the component of the same aspect as the above-mentioned embodiment, and the description is abbreviate|omitted.

As in the above-described embodiment, the tip portion 103 of the excavation tip 110 of this modified example has the convex curved portion 4 and the ridge portion 105 . Moreover, the ridge portion 105 has a thickest portion 6 having the largest protrusion height from the convex curved portion 4 .

The ridge portion 105 of this modified example has a widened portion 107 whose width dimension increases toward one side (+Y side) in the extending direction. In this modified example, the widened portion 107 is provided over the entire area in the extending direction of the ridge portion 105 . The width dimension of the widened portion 107 only needs to increase toward one side in the extending direction at least at the top surface 105b.

As in the above-described embodiment, the drilling tip 110 is attached so that the extending direction of the ridge portion 105 coincides with the radial direction of the axis O (see FIG. 5) of the tool body 11 . At this time, one side in the extending direction where the width dimension of the widened portion 107 of the projecting portion 105 becomes larger is arranged radially outside of the axis O. As shown in FIG.

According to the excavation tip 110 of this modification, the width dimension of the ridge portion 105 increases toward one side (+Y side) in the extending direction at the widened portion 107 . The drilling tip 110 is attached to the tool body 11 so that one side in the extending direction where the width dimension of the widened portion 107 increases is arranged radially outward of the axis O of the tool body 11 .

The drilling tip 110 is disproportionately radially outward of the axis O and significantly worn. For this reason, the width dimension of the protrusion 105 is increased on the radially outer side with respect to the axis O of the tool body 11 where wear tends to progress, and the wear of the protrusion 105 is suppressed from progressing locally in this area. can do. According to this modified example, even when the drilling tip 110 is used for a long period of time, the shape of the ridge portion 105 can be maintained, and a decrease in drilling efficiency can be suppressed. Moreover, according to this modification, the life of the excavation tip 110 can be further extended.

According to this modification, the widened portion 107 is provided over the entire length of the ridge portion 105 in the extending direction. Therefore, the width dimension can be adjusted in accordance with the amount of wear over the entire length of the protrusion 105 in the extending direction. As a result, the amount of wear over the entire length of the protrusion 105 can be appropriately controlled. However, the widened portion 107 does not necessarily have to be provided throughout the extending direction of the ridge portion 105 .

(Modification 2)
FIG. 19 is a side view of a drilling tip 210 of Modification 2 that can be employed in this embodiment. In addition, the same code|symbol is attached|subjected about the component of the same aspect as the above-mentioned embodiment, and the description is abbreviate|omitted.

As in the above-described embodiment, the tip portion 203 of the excavation tip 210 of this modified example has a convex curved portion 204 and a ridge portion 205 . Moreover, the ridge portion 205 has a thickest portion 206 with the largest protrusion height from the convex curved portion 204 .

The convex curved portion 204 of this modified example has a cannonball shape centered on the center line C. As shown in FIG. According to this modified example, by forming the projecting curved portion 204 into a cannonball shape, it is possible to increase the excavation efficiency and the excavation speed of the excavation tip 210 compared to the hemispherical shape. Further, as described above, since the ridge portion 205 of the excavation tip 210 has the thickest portion 206, excavation efficiency can be maintained even if wear progresses. That is, according to this configuration, it is possible to increase the excavation efficiency of the excavation tip 210 and suppress the decrease in the excavation efficiency even if the excavation proceeds.

Various embodiments of the present invention have been described above, but each configuration and combination thereof in each embodiment are examples, and addition, omission, replacement, and Other changes are possible. Moreover, the present invention is not limited by the embodiments.

DESCRIPTION OF SYMBOLS 1... Tip body 2... Base end part 3, 103, 203... Tip part 4, 204... Convex curved part 5, 105, 205... Ridge part 6, 206... Thickest part 6p... Vertex 10, 21, 110, 210... Drilling tip 11, 22... Tool body 12... Tip surface 20... Drilling tool 107... Widened part C... Center line D... Diameter hc, hp... Projection height O... Axis line W... Maximum value of width dimension α... Angle

Claims (13)

A drilling tip attached to a tip surface of a tool body that is rotated about an axis and applied with an impact force,
a tip body in which a columnar base end portion and a tip portion protruding from the base end portion toward the tip side are integrally formed;
The tip is
a convex curved portion protruding toward the tip side of the tip body;
a ridge extending in an extending direction along a diametrical direction with respect to the center line of the base end when viewed from the tip side of the tip body and protruding from the surface of the convex curved portion toward the tip side;
The ridge portion has a thickest portion with the largest protrusion height from the convex curved portion,
The vertex of the thickest part is arranged to be biased from the center line to one end side in the extending direction,
drilling tip. The protruding portion has the smallest protrusion height from the convex curved portion at both ends in the extending direction, and protrudes from the convex curved portion toward the thickest portion from both ends in the extending direction. The protrusion height of
The drilling tip of claim 1. The angle formed by the protruding direction of the thickest part and the center line is 0° or more and 45° or less.
A drilling tip according to claim 1 or 2. In the ridge portion, the protrusion height from the convex curved portion at the thickest portion is 1.0 times or more and 1.5 times or less the protrusion height from the convex curved portion on the center line. is
A drilling tip according to any one of claims 1-3. The width dimension of the ridge portion gradually decreases from the surface of the convex curved portion toward the tip side in the projecting direction,
A drilling tip according to any one of claims 1-4. Both ends of the ridge portion in the extending direction are located at a boundary portion between the base end portion and the tip end portion,
A drilling tip according to any one of claims 1-5. The maximum value of the width dimension at the root portion of the ridge portion connected to the convex curved portion is in the range of 1/3 or more and 3/4 or less of the diameter D of the base end portion.
A drilling tip according to any one of claims 1-6. The convex curved portion is a hemispherical shape centered on the center line,
A drilling tip according to any one of claims 1-7. The convex curved portion has a cannonball shape centered on the center line,
A drilling tip according to any one of claims 1-7. The protrusion height of the ridge portion at the thickest portion from the convex curved portion is in the range of 9/100 or more and 30/100 or less of the diameter of the base end portion.
A drilling tip according to any one of claims 1-9. The ridge portion is formed of a polycrystalline diamond sintered body,
A drilling tip according to any one of claims 1-10. The ridge portion has a widened portion whose width dimension increases toward one side in the extending direction,
A drilling tip according to any one of claims 1-11. A drilling tip according to any one of claims 1 to 12;
a tool body that holds the drilling tip on the tip surface and is rotated around the axis;
The drilling tip has the tip portion projected from the tip end surface, the extending direction of the ridge portion is aligned with the radial direction with respect to the axis of the tool body, and the apex is arranged in a biased manner. Arranging one end side in the extending direction radially outward of the axis,
drilling tools.

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