JPH10146771A - Diamond bit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a diamond bit in which cutting performance in an initial stage is high, in which continuity performance of the cutting performance is improved, in which cut chip discharge performance is favorable, and in which service life is long. SOLUTION: In diamond but, plural cut parts 4 are formed at contact parts of a diamond segment chip 3 with subject members, thus an angular part 5 of the cut part 4 becomes a cutting blade to provide edge effect, and a bottom surface of the cut part 4 is inclined in a radial direction. Because cut chip discharge performance is thus favorable, adverse effects of cut chip are not exerted in boring, and breakage of the segment chip 3 can be effectively prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a diamond bit for excavating a stone or the like.

[0002]

2. Description of the Related Art Diamond bits are classified into a surface set diamond bit and an implanted diamond bit according to a diamond planting method.

[0003] A surface set diamond bit is one in which small grains are implanted on the cutting edge surface, and an implanted diamond bit is one in which fine grains are mixed with an alloy and sintered.

[0004] The present invention relates to an implanted diamond bit, and the rotational speed and the load of the diamond bit are closely correlated. That is, a diamond bit rotating at a constant speed in a uniform rock increases the excavation rate in proportion to the pressure applied to the diamond bit, and reaches an optimum state of the bit and the work. Further increasing the pressure does not correspondingly increase the cutting speed, and at this stage a higher cutting speed can only be obtained by increasing the rotational speed. Here, when cutting using a diamond bit, it is necessary to send a circulating fluid into the hole for cooling the bit and discharging chips. As the fluid, fresh water, muddy water, compressed air, or the like is used, but the above relationship is based on the assumption that the above-described cooling water volume and pressure are under ideal conditions.

[0005] Usually, an appropriate rotation speed is represented by a peripheral speed of the outer periphery, and as a guide, 300 to 720 feet / min is used for an integrated diamond bit.

[0006] The diamond bit is loaded,
Heat is generated by rotation. Also, since the chips of the cut chips play around the diamond, these particles are quickly removed from the diamond cutting point, and in order to cool the diamond surface, water holes or water grooves are usually formed on the bit surface. Is provided.

[0007] In order to discharge chips, the circulating fluid needs to have a constant flow rate, and the circulating fluid must be large enough to transport the particles and the specific gravity of the chips.
That is, a flow rate that is at least three to four times the sedimentation velocity of the particles is required.

From this viewpoint, Japanese Utility Model Laid-Open No. 61-24111 and Japanese Patent Laid-Open No. 3-245974 have been proposed as improved diamond bits.

That is, the former diamond bit 01
As shown in FIG. 9, an annular segment chip 03 having a radial cutting edge 02 is fixed to a tip of a cylindrical shank 05 via a base metal 04. The radial cutting edge 02 formed at the tip of the hard sintered body 03 has a rake angle in the radial direction, a rake angle in the axial direction, and a clearance angle to improve the initial sharpness.

The latter diamond bit 01 is
As shown in FIG. 10 (a), a chip discharge groove is provided alternately on both the inner and outer surfaces of the segment chip. A plurality of segment chips 08 are fixed to the tip of the cylindrical body 07 at intervals, and are attached to this segment chip. A chip discharge groove 09 is provided.

FIG. 10A is a front view of the tip of a diamond bit, FIG. 10B is a sectional view taken along line II of FIG.
(C) shows a cross-sectional view taken along the line JJ.
No. 9, when the depth t of the chip discharge groove 09 is at least half the thickness T of the cutting edge, wear progresses on average, and the dressing of diamond abrasive grains in the segment chip is always repeated. As a result, stable cutting properties are always obtained.

[0012]

However, in the former case, a valley 06 is formed at the tip of the segment chip by an inclined portion extending from the clearance angle and a rake angle, and the valley 06 is formed on the inner periphery of the segment chip. Alternatively, since there is no clearance angle in the outer peripheral direction, chips and dropped diamond abrasive grains accumulate in the valleys 06, and the discharge of the chips is poor, which is an obstacle to excavation and lowers the excavation rate. Had.

In the latter case, by forming the chip discharge groove 09 having a predetermined depth, the radial thickness of the segment chip serving as a cutting edge is reduced, and the thin portion is the same in the axial direction. Since it is formed to have a thickness, the rigidity of this portion is reduced, which results in breakage of the segment chip.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a diamond bit having a high initial sharpness and a high excavation rate, a good discharge of chips and the like, and a long life. And

[0015]

SUMMARY OF THE INVENTION According to the present invention, a diamond segment tip is attached at a predetermined interval to the tip of an annular cylindrical body which is driven to rotate, and the diamond segment tip is in contact with a workpiece from an inner surface or an outer surface. A plurality of recesses are cut into the side surface, and the recesses are characterized in that the bottom surface is inclined at least in the radial direction. According to this feature, since a plurality of concave portions are formed at the contact portion of the diamond segment tip with the workpiece, the corners of the concave portions serve as cutting edges to exert an edge effect, and the bottom surface of the concave portion is formed. Since it is inclined in the radial direction and is open to the inside or outside, the chip discharge performance is improved. Further, according to the structure of the concave portion,
Since the root of the diamond segment tip is inevitably gradually thicker, there is no fear of breakage of the segment tip during excavation.

The diamond bit according to the present invention is characterized in that the concave portions are alternately arranged toward the inner peripheral side and the outer peripheral side of the diamond bit. According to this feature, since the concave portions are alternately arranged toward the inner peripheral side and the outer peripheral side of the diamond bit, the wear shape of the bit can be prevented from being biased, and stable excavation can be performed.

The diamond bit according to the present invention is characterized in that the concave portion is formed in a substantially U shape at the front end of the diamond bit when viewed from the front. According to this feature, since the concave portion is formed in a substantially U-shape at the front end of the diamond bit when viewed from the front, the corner of the concave portion becomes a cutting edge perpendicular to the rotation direction of the diamond bit, and the sharpness is good due to a high edge effect, In addition, the chip discharge efficiency can be increased.

The diamond bit of the present invention is characterized in that the concave portion is formed in a substantially triangular shape at the front end of the diamond bit when viewed from the front. According to this feature, since the concave portion is formed in a substantially triangular shape at the front end of the diamond bit when viewed from the front, one side of the triangle serves as a cutting edge to have an edge effect, and the rigidity of the segment tip can be maintained even higher. .

The diamond bit of the present invention is characterized in that the concave portion is formed in a substantially right triangle having a part of the circumference as the base. According to this feature, since the concave portion is formed in a substantially right triangle with a part of the circumference as the base, the vertical side of the right triangle becomes a cutting edge perpendicular to the rotation direction of the diamond bit, and has a high edge effect. In addition, the rigidity of the segment chip can be maintained high.

In the diamond bit of the present invention, the diamond segment tip has a contact surface with the work material of 50 to 50%.
It is characterized by 98%. According to this feature, the contact surface with the workpiece is maintained at 50 to 98%, so that the average supply pressure can be increased and the excavation rate can be increased.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments and the drawings. An embodiment of the diamond bit of the present invention will be described.

FIG. 1 is a front view showing the tip of a diamond bit, FIG. 2A is a sectional view taken along line AA of FIG.
(B) is a view on arrow B of FIG. 1, (c) is a cross-sectional view taken along line CC of FIG. 1, and (d) is a cross-sectional view taken along line DD of FIG. 1.

In the figure, reference numeral 1 denotes a diamond bit, and the diamond bit 1 has a diamond segment tip 3 attached to a tip end of a base metal 2 of a circular cylinder which is driven to rotate at a constant interval.

More specifically, in the case of an implanted bit, the diamond segment chip 3 is manufactured by previously mixing a matrix with small particles of fragment boats or synthetic diamond, and pressing and sintering as a segment. It is brazed or integrally sintered to the gold 2.

Then, the diamond segment tip 3
In the center, a U-shaped notch 4 as a concave portion is formed as a recess, and the notch 4 is disposed toward the inner peripheral edge and the outer peripheral edge of the diamond bit 1. The bottom surface is formed to be alternately inclined in the opposite direction toward the radial direction.

Here, the corner 5 formed by the notch 4 and the contact surface of the diamond segment tip 3 with the workpiece is a cutting edge when the diamond bit 1 is driven to rotate in the direction of the arrow, and this width is reduced. A large value has an edge effect and improves initial sharpness.

Next, the operation of the diamond bit will be described. First, as shown in FIG. 1, the diamond bit 1 is rotated while the diamond segment tip attached to the tip of the base metal at a fixed interval is pressed against and contacts a work material (not shown). Supply drilling fluid to

When the diamond bit 1 is driven to rotate, the shavings and diamond particles detached from the bond are guided by the radially extending inclined surface of the notch 4 and flow out together with the drilling liquid, and are discharged to the outside. Is done.

Therefore, no sludge, slime, chips and the like remain in the notch 4 of the diamond bit 1 facing the excavation hole, and the sharpness of the diamond bit 1 is not reduced.

In the present embodiment, the notch 4 is formed in a part of the diamond segment tip 3, and the contact area between the diamond segment tip 3 and the work material is reduced to 100% without the notch 4. If done, 50-98%
Can be contacted in the range. This means that the pressing force on the contact surface can be increased, and the corner portion 5 of the notch 4 serves as a cutting edge to enhance the edge effect, thereby increasing the initial bite amount and excavating. Rate can be promoted.

The diamond segment tip 3 is shown in FIG.
As shown by the two-dot chain line, as the excavation wears out from the tip surface, the area of the notch 4 gradually decreases and the contact area increases, but the shape of the notch 4 In addition, since the diamond segment tip 3 becomes thicker toward the base (the base metal, the diamond segment and the joint thereof), even if a large unexpected load is applied to the diamond segment 3 during cutting, There is no damage such as tooth spilling. In other words, even if many notches 4 are formed, there is no fear of tooth spilling or the like.

Next, the results of excavation tests performed for the purpose of comparing the performance of the diamond bit 1 according to the shape of the excavated surface are shown in Table 1.

[0033]

[Table 1] The test result shows that the excavated surface is 86% at a load of 800 kgf.
Had a stable sharpness, no tooth spills, and maintained a stable shape.

Next, the radar chart shown in FIG.
In the case of an area of 100%, the digging length, the digging time, the average digging rate, and the average cumulative value of the life of a load of 800 kgf are shown.

The radar chart shown in FIG.
In the case of 6%, the excavation length, the excavation time, the average excavation rate, and the average cumulative value of the service life of a load of 800 kgf are shown.

Compared with the area of 100%, particularly, the life, the excavation length and the excavation time were increased, showing excellent results.

Next, another embodiment will be described.

FIG. 4 is a front view showing the tip of a diamond bit according to a second embodiment. A U-shaped notch formed in the diamond segment tip 3 is provided at the center of the diamond segment tip 3. Notched portions 6 having different inclination directions are provided on both sides of the notched portion 4, and are alternately arranged at the contact portions of the diamond segment chips 3 with the workpiece. In this case, the contact area with the workpiece is reduced, and the edge effect is improved, so that the excavation rate is significantly improved.

FIG. 5A is a front view showing a tip of a diamond bit according to a third embodiment, FIG. 5B is a sectional view taken along line EE of FIG. 5A, and FIG. FIG.

In this embodiment, the notch formed in the diamond segment tip 8 has a triangular shape when viewed from the front, and the notch 9 provided at the center of the diamond segment tip 8 has cuts having different inclination directions on both sides. Notches 10 are provided, and are alternately arranged at the contact portions of the diamond segment tips 8 with the workpiece.

The corner 11 formed by one side of the triangular notch 9 and the contact surface of the diamond segment tip 8 with the workpiece is a cutting edge when the diamond bit 7 is driven to rotate in the direction of the arrow. By increasing the width, an edge effect is obtained and the initial sharpness is improved.

FIG. 6A is a front view showing the tip of a diamond bit according to a fourth embodiment, FIG. 6B is a sectional view taken along line GG of FIG. 6A, and FIG. FIG.

In this embodiment, the notch formed in the diamond segment tip 13 has a right-angled triangular shape when viewed from the front, and the inclination direction differs on both sides of the notch 14 provided at the center of the diamond segment tip 13. Notches 15 are provided, and are alternately arranged at the contact portions of the diamond segment tips 13 with the workpiece.

Here, the corner 16 formed by the vertical side of the cut portion 14 of the right triangle and the contact surface of the diamond segment tip 13 with the workpiece is formed when the diamond bit 12 is driven to rotate in the direction of the arrow. It becomes a cutting edge and this corner 1
Since the ridge line of No. 6 coincides with the radial direction, the edge effect is improved. Further, this embodiment is particularly effective when it is desired to increase only the edge effect without making the contact area between the workpiece and the diamond segment tip extremely small.

In general, in the initial stage of excavation, since the segment chips are long in the axial direction, it is difficult to discharge swarf satisfactorily. As the wear of the segment chips further progresses, the length of the segment chips in the axial direction becomes shorter, so that the above-described chip discharge is relatively better than in the initial stage, but the segment chips themselves are Rigidity decreases over time and becomes susceptible to breakage.
Here, the segment chip of each of the embodiments described above is appropriately adapted to such a cutting mechanism, and in the initial stage of cutting, the ratio of the concave portion is large, and the discharge of chips is favorably promoted. Since the ratio of the recesses is small, the rigidity of the segment chip is maintained.

Although the embodiments of the present invention have been described with reference to the drawings, the specific configuration is not limited to these embodiments, and even if there are changes and additions without departing from the gist of the present invention. Included in the invention.

[0047]

The present invention has the following effects.

(A) According to the first aspect of the present invention, since a plurality of concave portions are formed at the contact portion of the diamond segment tip with the workpiece, the corner portion of the concave portion serves as a cutting edge to provide an edge effect. And the bottom surface of the concave portion is inclined in the radial direction and is open to the inside or outside, so that the chip discharge performance is improved. Furthermore, according to the structure of the concave portion, the root of the diamond segment tip is inevitably gradually thickened, so that there is no fear of breakage of the segment tip during excavation.

(B) According to the second aspect of the present invention, since the concave portions are alternately arranged toward the inner peripheral side and the outer peripheral side of the diamond bit, the wear shape of the bit can be prevented from being unbalanced and stable. Digging is possible.

(C) According to the third aspect of the present invention, since the concave portion is formed in a substantially U shape at the front end of the diamond bit, the corner of the concave portion becomes a cutting edge perpendicular to the rotation direction of the diamond bit. In addition, sharpness can be improved due to a high edge effect, and the efficiency of chip discharge can be increased.

(D) According to the fourth aspect of the present invention, since the concave portion is formed in a substantially triangular shape at the front end of the diamond bit when viewed from the front, one side of the triangular shape serves as a cutting edge to have an edge effect, and the segment chip has Rigidity can be maintained even higher.

(E) According to the fifth aspect of the present invention, since the concave portion is formed in a substantially right triangle having a part of the circumference as the base,
The vertical sides of the right triangle become cutting edges that are perpendicular to the direction of rotation of the diamond bit, have a high edge effect, and can maintain high rigidity of the segment tip.

(F) According to the invention of claim 6, since the contact surface with the workpiece is maintained at 50 to 98%, the average supply pressure can be increased and the excavation rate can be increased. it can.

[0054]

[Brief description of the drawings]

FIG. 1 is a front view showing a tip of a diamond bit as one embodiment of the present invention.

2A is a sectional view taken along line AA of FIG. 1, FIG. 2B is a sectional view taken along arrow B of FIG. 1, FIG. 2C is a sectional view taken along line CC of FIG. 1, and FIG. It is DD sectional drawing.

FIG. 3 is a partial perspective view of a diamond segment tip.

FIG. 4 is a front view showing a diamond bit tip as a second embodiment.

FIG. 5 (a) is a front view showing a diamond bit tip according to a third embodiment, and FIG. 5 (b) is a view showing E of FIG.
It is E sectional drawing, (c) is an arrow F view of (a).

FIG. 6A is a front view illustrating a diamond bit tip according to a fourth embodiment, and FIG. 6B is a front view of G of FIG.
FIG. 6C is a cross-sectional view of FIG. 7G, and FIG.

FIG. 7 is a radar chart of a performance test of a standard diamond bit.

FIG. 8 is a radar chart of a performance test of a diamond bit as one sample of the present invention.

FIG. 9 is a side view of a conventional diamond bit.

10A is a front view showing the tip of a conventional diamond bit, FIG. 10B is a sectional view taken along line II of FIG. 10A, and FIG. 10C is a sectional view taken along line JJ of FIG. It is.

[Explanation of symbols]

 1, 7, 12 diamond bit 2 base metal 3, 8, 13 diamond segment chip 4, 6, 9, 10, 14, 15 notch (recess) 5, 11, 16 corner

Claims (6)

[Claims] 1. A diamond segment tip is mounted at a predetermined interval on a tip end of an annular cylinder that is driven to rotate, and a plurality of recesses are cut from a contact surface of the diamond segment tip with a workpiece to an inner surface or an outer surface. The diamond bit is characterized in that the recess has a bottom surface inclined at least in a radial direction. 2. The diamond bit according to claim 1, wherein the recesses are alternately arranged toward an inner peripheral side and an outer peripheral side of the diamond bit. 3. The diamond bit according to claim 1, wherein the recess is formed in a substantially U-shape at the front end of the diamond bit when viewed from the front. 4. The diamond bit according to claim 1, wherein the recess is formed in a substantially triangular shape at the front end of the diamond bit when viewed from the front. 5. The diamond bit according to claim 4, wherein the recess is formed in a substantially right triangle having a part of a circumference as a base. 6. The diamond segment tip,
The diamond bit according to any one of claims 1 to 5, wherein a contact surface with the workpiece is 50 to 98%.