JP5719680B2 - Perforation bit - Google Patents

Description

  The present invention is provided with a plurality of chips made of cemented carbide of various chip shapes such as a house shape, spike shape, button shape, etc. on the base metal, and the vibration in the front-rear direction is shifted while shifting the position where the plurality of chips hit by rotation. The present invention relates to a drilling bit that performs drilling by giving an impact to an object to be drilled.

  As a drill bit tip that is attached to the tip of a rock drill, rock bolt, etc., and impacts the drilling target by vibration in the front-rear direction while shifting the position where the plurality of tips hit, A so-called house-shaped bit (see, for example, Patent Documents 1 and 2) provided with a plurality of hard alloy blades (double-edged tip), or a button-shaped bit provided with a cemented carbide button-like tip (eg, Patent Document 3).

  For example, when a drill bit employing such a chip made of cemented carbide is used by being attached to the tip of a rock bolt, the axis direction of the drill bit is approximately 10 times as many as several hundred revolutions per minute. By moving back and forth (vibration) in the forward and backward direction, the object to be drilled such as rock is hit, and compressed air is discharged from the blow hole provided in the drill bit, and self-drilled by the compressed air discharged from the blow hole. While discharging slime (chip powder) in the direction of the rear end of the lock bolt, a long hole having a hole diameter corresponding to the maximum outer diameter of the drill bit is formed and advanced.

Japanese Patent Laid-Open No. 11-170035 JP-A-8-31280 JP 2004-156222 A

  By the way, if there is a step or the like on the guide surface of the base metal as in the drilling bits described in Patent Document 1 and Patent Document 3 described above, and FIGS. When pulling back a rock bolt or drilling bit provided at the tip of a rock drill depending on the discharge situation, a large slime is easily caught on the step, and a large force is required for the pulling operation. There is a possibility that it may not be possible, and this will hinder drilling operations. In addition, the connecting surface side, which is the rear end portion of the drill bit, is not a portion that directly hits the chip, as compared to the tip mounting surface side, which is the tip portion where the tip such as a blade body or a button-shaped tip is provided. There is no problem even if it is formed thinner than the mounting surface side. Therefore, in consideration of such pulling-back operation of the drilling bolt, striking, and the like, the guide surface of the drilling bit is like a drilling bit described in FIG. It is desirable that the diameter gradually decreases as it goes to the connecting surface side, which is a portion.

  However, the perforated bit described in FIG. 3 of Patent Document 2 has a problem in that the blow hole is opened at the tip mounting surface on the tip side, and the slime discharge performance is poor.

  Further, in order to improve the slime discharge performance, it is generally necessary to ensure a large cross-sectional area of the discharge groove formed by the discharge groove surface between the guide surfaces. If a wide width is ensured, the length of the guide surface in the circumferential direction becomes small, and there arises a problem that the rectilinearity of the drill bit that moves in the front-rear direction by vibration while rotating is reduced. In particular, in the drill bit using an expensive cemented carbide blade, the cost decreases as the number of cemented carbide blades (tips) decreases, and the impact force increases against hard rock. Since the number of bodies (chips) is small, misalignment, i.e., the rotation axis, is likely to shift, so the straight guide function that the guide surface, which is the outermost peripheral surface of the base metal, plays an important role. It is necessary to ensure a large thickness.

  Therefore, the present invention provides a drill bit in which the slime does not adversely affect the pull-back operation, and the length of the guide surface in the circumferential direction is ensured and the straightness is improved while ensuring the slime discharge performance. For the purpose.

In order to achieve the above object, the drill bit according to the present invention is provided with a plurality of chips on a base metal, and applies an impact to the drilled object by vibration in the front-rear direction while shifting the position where the plurality of chips hit by rotation. A drill bit for drilling, wherein the base metal includes a connection surface to which tip portions such as a rock drill and a rock bolt are connected, a chip holding surface on which a plurality of chips are arranged, the connection surface and the chip A plurality of guide surfaces having a peripheral side surface with the center of the drilling bit as an axis for maintaining straightness during drilling between the holding surface and the guide surfaces are recessed from the guide surfaces between the guide surfaces. An outer peripheral side surface including a plurality of discharge groove surfaces that form discharge grooves for discharging generated slime, and each of the plurality of guide surfaces extends from the tip holding surface to the connecting surface. Approach While is inclined urchin tapered closest portion to the axis of the drilling bit in the plurality of discharge groove surface are each a constant inclination angle so as to approach the axis of the drilling bit closer to the chip holding surface The tip holding surface is inclined without a step to reach the tip holding surface, and a blade body holding seat portion for fixing a plurality of tips is formed on the tip holding surface, and the blade body holding seat portion is anti-rotated. Only the end on the direction side is located on the boundary line between the guide surface and the discharge groove surface .
As a result, each of the plurality of guide surfaces is inclined in a tapered shape so as to approach the axis of the perforating bit from the chip holding surface to the connection surface, so that the pull back operation performed when the slime is supported in the drilling hole, etc. Can be adversely affected . Further, the portions of the plurality of discharge groove surfaces that are closest to the axis of the perforation bit are inclined in a tapered manner without a step at a certain inclination angle so as to approach the axis of the perforation bit as they approach the chip holding surface. A blade holding seat for fixing a plurality of chips is formed on the chip holding surface, and only the end on the counter-rotating direction side of the blade holding seat is the guide surface and the discharge groove. Since it is configured to be located on the boundary line with the surface, even when the circumferential length in the rotation direction of the drill bit on the guide surface is ensured in order to ensure the straightness of the drill bit, the perforation of the blade holding seat portion Since the discharge groove surface starts immediately from the end on the counter-rotation direction side, the slime discharge performance can be improved. As a result, it is possible to improve the straightness by ensuring a large circumferential length of the guide surface while ensuring slime discharge.
Here, the base metal is further formed at the center of the drilling bit from the connection surface toward the tip holding surface, and a connection hole to which a hollow tip such as the rock drill or the rock bolt is connected. A plurality of blow holes that are branched from the connection hole toward the plurality of discharge groove surfaces and that open at each of the plurality of discharge groove surfaces and discharge compressed air. The blow holes may be provided so as to be inclined with respect to the perpendicular line on the discharge groove surface provided with each blow hole.
In this case, when the cross section of the blowhole is circular, the shape of the blowhole opening becomes an elliptical shape, and the area of the shape of the blowhole opening becomes large without increasing the inner diameter of the blowhole. Since the range of compressed air is expanded, the slime discharge performance can be further improved without reducing the strength of the base metal by increasing the inner diameter of the blow hole.
Further, among the plurality of blow holes, at least one blow hole is inclined toward the tip holding surface side with respect to a perpendicular to the discharge groove surface where the blow hole is provided, while another blow hole is provided. The hole may be provided so as to be inclined toward the connecting surface with respect to a perpendicular line on the discharge groove surface provided with the blow hole.
In this case, since the direction of the compressed air discharged from the plurality of blowholes faces diagonally forward and diagonally rearward, coupled with the rotation of the drill bit, the slime discharge performance can be further improved. it can.

In the perforated bit of the present invention, each of the plurality of guide surfaces is tapered so as to approach the axis of the perforated bit from the chip holding surface to the connecting surface, while the perforated bit of the perforated bit on the plurality of discharge groove surfaces. The portion closest to the axis reaches the tip holding surface by inclining in a tapered manner without a step at a certain inclination angle so as to approach the axis of the perforated bit as it approaches the tip holding surface. A blade body holding seat portion for fixing a plurality of chips is formed, and only the end of the blade body holding seat portion on the counter-rotating direction side is located on the boundary line between the guide surface and the discharge groove surface. For this reason, the slime does not adversely affect the pull-back operation, and the length of the guide surface in the circumferential direction can be ensured and the straightness can be improved while ensuring the slime discharge performance.

It is a top view of the drilling bit of embodiment. (A), (b) is the II sectional view taken on the line of the punching bit of embodiment, and the II-II sectional view, respectively. FIGS. 2A and 2B are a left side view and a right side view of the drill bit according to the embodiment shown in FIG. 1, respectively. It is a figure which shows the state which connected the lock bolt to the drill bit of embodiment, and is drilling as a self-drilling lock bolt. It is a top view which shows the other example of the punch bit of embodiment. It is a top view which shows the further another example of the punching bit of embodiment. It is a top view which shows the further another example of the punching bit of embodiment.

  Hereinafter, embodiments of a perforated bit according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a plan view of a drill bit according to the embodiment, and FIGS. 2A and 2B are a cross-sectional view taken along line II, II-II, and FIG. 3, respectively, of the drill bit according to the embodiment. FIGS. 2A and 2B are a left side view and a right side view of the drill bit according to the embodiment shown in FIG. 1, respectively.

  The drill bit A of the embodiment is attached to the tip of a rock drill, a rock bolt, or the like, for example, and as shown in FIGS. A plurality of (in this embodiment, for example, three for convenience) blade bodies 2a to 2c are provided, and the positions where the plurality of blade bodies 2a to 2c come into contact with each other by rotation are shifted while rotating in the front-rear direction due to vibration. It is a drill bit that drills by impacting a drilling object such as various rocks such as hard or soft by operation.

  Here, the number of rotations of the perforation bit A is, for example, about 200 rotations per minute, and the number of hits caused by vibration in the front-rear direction is about 1800 times per minute. That is, the rotation speed is 9 times, and the position where the blades 2a to 2c hit is rotated by rotating the perforation bit A by 40 degrees by one stroke, and the rotation is performed once by nine strokes.

  Here, the blades 2a to 2c, which are house-shaped chips, are made of a cemented carbide such as tungsten carbide, for example. Therefore, the blades 2a to 2c are expensive, and it is required to reduce the number of the blades 2a to 2c as much as possible in the drill bits for self-drilling lock bolts that are supposed to be used only once. The blades 2a to 2c have tips formed at acute angles.

  The base metal 1 includes a connection surface 11 to which a tip portion (not shown) such as a rock drill or a rock bolt is screwed, a chip holding surface 12 on which a plurality of blade bodies 2a to 2c are disposed, and a connection surface 11. A plurality of guide surfaces 13a1 to 13a3 having a peripheral side surface with the center C of the perforation bit A as an axis in order to maintain straightness during drilling (drilling), and the guide surfaces 13a1 to 13a1 13a3 and an outer peripheral side surface 13 provided with discharge groove surfaces 13b1 to 13b3 for forming a plurality of discharge grooves 13b11 to 13b31 for discharging slime generated during drilling.

  Here, in the drill bit A of the present embodiment, the plurality of guide surfaces 13a1 to 13a3 are all on the tip side as shown in FIGS. 2 (a) and 2 (b) and FIGS. 3 (a) and 3 (b). From a certain chip holding surface 12 to the connecting surface 11 on the rear end side, it approaches the axis CL of the perforating bit A and is tapered, that is, straight, and inclined without a step.

  Therefore, according to the perforated bit A of the present embodiment, as shown in FIG. 4 described later, the slime broken by the perforated bit A can be prevented from being caught by a step on the guide surface, and the slime is perforated (drilled) wall. Can be prevented from adversely affecting the pulling-back operation of the perforated bit A performed when it is supported between the perforated bit A and the like.

  On the other hand, the portions of the plurality of discharge groove surfaces 13b1 to 13b3 that are closest to the axis CL of the perforation bit, that is, the central portions of the plurality of discharge groove surfaces 13b1 to 13b3 are shown in FIGS. 1 and 2A, 2B. As shown in the figure, all of them are tapered and straight so as to be closer to the axis CL of the perforated bit A as they approach the chip holding surface 12, and are inclined without any step.

  Therefore, according to the drilling bit A of this embodiment, the depth of the discharge groove surfaces 13b1 to 13b3 in the axial direction CL of the drilling bit A increases as the discharge groove surfaces 13b1 to 13b3 approach the chip holding surface 12. Since the cross-sectional area of the discharge grooves 13b11 to 13b31 increases, even if the circumferential length of the guide surfaces 13a1 to 13a3 is ensured to improve straightness, the gap between the discharge groove surfaces 13b1 to 13b3 and the hole wall is increased. It becomes possible to ensure the cross-sectional area of the discharge path to be formed, and to ensure a large length in the circumferential direction of the guide surfaces 13a1 to 13a3 while ensuring the slime discharge performance, it is possible to improve the straightness. In addition, since the outer diameter of the base metal 1 becomes smaller as it approaches the connecting surface 11, even if the cross-sectional area of the discharge grooves 13 b 11 to 13 b 31 is reduced, there is no problem in the slime discharge performance, and both ends of the base metal 1. Sufficient strength can be secured for the portion.

  Further, as shown in FIGS. 2A and 2B, the connection surface 11 has a connection hole 11a such as a screw hole into which a tip portion (not shown) such as a rock drill or a rock bolt is screwed. Is formed. A compressed air reservoir 11a2 for branching compressed air sent through a hollow hole (not shown) such as a rock drill or a rock bolt to the blow holes 13b12 to 13b32 is provided at the tip of the connecting hole 11a. Is provided.

  The chip holding surface 12 has a plurality of blade bodies 2a to 2c arranged at an angle of 120 degrees with respect to the center C of the perforation bit, spaced apart from the center side of the plurality of blade bodies 2a to 2c, and fixed by brazing or the like. Therefore, a blade body holding seat 121 having a concave cross section that is widened by the width of the blade bodies 2a to 2c at an angle of 120 degrees from the center C of the drill bit is formed.

  And in the chip | tip holding surface 12 of this Embodiment 1, several blade body 2a-2c is made into the rotation direction (alpha) of the said perforation | biting bit A in the guide surfaces 13a1-13a3 on the basis of the arrangement position of each blade body 2a-2c. It arrange | positions so that the circumferential direction length may become longer than the circumferential direction length of the counter rotation direction (beta) of the said drill bit A in the guide surfaces 13a1-13a3. In other words, in other words, the plurality of blades 2a to 2c are respectively shifted to the tip holding surface 12 from the circumferential center position of the guide surfaces 13a1 to 13a3 toward the counter-rotation direction β side of the drill bit. Are fixed by brazing.

  For example, in the case of the blade body 2b, as shown in FIG. 3B, the guide surface with reference to an extension line 13a2CL extending in parallel with the axial direction of the drill bit A from the outermost blade tip of the blade body 2b. The circumferential length 13a2L1 in the rotational direction α of the drilling bit A at 13a2 is arranged on the chip holding surface 12 so as to be longer than the circumferential length 13a2L2 in the counter-rotating direction β of the drilling bit A in the guide surface 13a2. . The other blades 2a and 2c are also in the same position as the blade 2b as described above.

  Therefore, in the drill bit A of the first embodiment, the circumferential length in the rotation direction α of the drill bit A on the guide surfaces 13a1 to 13a3 is the guide surfaces 13a1 to 13a3 with the arrangement positions of the plurality of blade bodies 2a to 2c as the center. Is longer than the circumferential length of the perforating bit A in the counter-rotating direction β, so that the slime (cutting powder) that moves the blades 2a to 2c in the counter-rotating direction β along with the rotation is located near the discharge groove. It becomes easy to enter 13b11-13b31. For this reason, it becomes possible to ensure the length of the guide surfaces 13a1 to 13a3 in the circumferential direction while ensuring the slime discharge performance, and the straightness of the drill bit A can be improved. In the present invention, it is optional to change the circumferential lengths of the rotation direction α and the counter-rotation direction β of the perforation bit A on the guide surfaces 13a1 to 13a3, and the rotation direction α and the counter-rotation of the perforation bit A are optional. Of course, the circumferential length in the direction β may be the same.

  Further, in the punch bit A of the embodiment, the end portions 121a1 to 121c1 on the counter-rotating direction β side of the drill bit A in the blade holding seat 121 are guide surfaces 13a1 to 13a1 on the counter-rotating direction β side of the punch bit A. It is located on the boundary line between 13a3 and the discharge groove surfaces 13b1 to 13b3.

Therefore, in the drill bit A of the embodiment, even when the circumferential length in the rotation direction of the drill bit A on the guide surfaces 13a1 to 13a3 is secured in order to ensure the straightness of the drill bit A, the blade holding seat 121 Since the discharge groove surfaces 13b1 to 13b3 start immediately from the end portions 121a1 to 121c1 on the counter-rotation direction β side of the perforation bit A, coupled with the effect of the discharge grooves 13b11 to 13b31 formed in the above-described inclination, in this respect, Ru can improve the discharge of the slime.

  Of the three blow holes 13b12 to 13b32 of the drill bit A, the blow hole 13b32 is inclined obliquely rearward of the drill bit A and has a discharge groove surface 13b3 as shown in FIG. It is inclined with respect to the perpendicular. Although not shown in the sectional view, as shown in FIG. 3B, the blow hole 13b22 is also inclined to the rear end side of the perforated bit A, that is, the connecting surface 11 side, like the blow hole 13b32. And it inclines with respect to the perpendicular | vertical in the discharge groove surface 13b2.

  On the other hand, of the three blow holes 13b12 to 13b32 of the drill bit A, only the blow hole 13b12 is inclined obliquely forward of the drill bit A as shown in FIG. It inclines with respect to the perpendicular in 13b1.

  Thereby, according to the punching bit A of the embodiment, when the cross section of each of the blow holes 13b12 to 13b32 is circular, the shape of the opening of each of the blow holes 13b12 to 13b32 becomes an elliptical shape, and the blow holes 13b12 to 13b32 Even if the inner diameter of the blow hole is not increased, the area of the opening of each of the blow holes 13b12 to 13b32 is increased, so that the compressed air ejection range is widened. In this respect as well, the slime discharge performance can be improved. In particular, the blow holes 13b22 and 13b32 that open obliquely rearward are inclined so that the discharge groove surfaces 13b2 and 13b3 approach the axis CL as the discharge groove surfaces 13b2 and 13b3 approach the chip holding surface 12. It becomes.

  In addition, since the perforated bit A according to the embodiment includes the blow hole 13b12 formed obliquely forward and the blow holes 13b22 and 13b32 formed obliquely backward, the three blow holes 13b12 to 13b32 are provided. Therefore, the compressed air is discharged diagonally forward and diagonally backward, and in combination with the rotation of the perforation bit A, slime can be effectively discharged also in this respect. In addition, the angle of each blowhole 13b12-13b32 is arbitrary in this invention.

  FIG. 4 is a diagram illustrating a state in which the lock bolt B is connected to the drill bit A according to the embodiment and drilling is performed as a self-drilling lock bolt.

  As shown in FIG. 4, in the perforated bit A of the embodiment, the shape of the outer peripheral side surface 13 of the base metal 1 becomes thinner from the tip mounting surface 12 side which is the front end side toward the connecting surface 11 side which is the rear end side. In comparison with the case where there is a step or the like on the outer peripheral side surface 13 of the base metal 1, the self-drilling lock bolt is When trying to pull back, the slime easily moves smoothly between the drilling wall and the drill bit A or the lock bolt B, the pull-back operation of the self-drilling lock bolt becomes smooth, and operability (workability) is improved. improves.

  In the perforation bit A of the present embodiment, as shown in FIGS. 1 to 4, a plurality of blade bodies 2 a to 2 d at an angle of 120 degrees with respect to the center C of the perforation bit A on the blade body holding seat 121. Although the center side of 2c was separated and fixed and explained, in the present invention, it is not limited to this, and as shown in FIG. 5, a plurality of blade bodies 2a to 2c shown in FIG. Needless to say, the blades 2a 'to 2c' may be present up to the position of the center C using the blades 2a 'to 2c'.

  In the embodiment drill bit A, the plurality of blades 2a to 2c are described to be arranged at intervals of 120 degrees. However, in the present invention, the present invention is not limited to this, and two blade bodies are arranged at intervals of 180 degrees, for example. That is, of course, it may be arranged in a single character, or four or more may be arranged at equal intervals. As a result, the number of guide surfaces, discharge groove surfaces, blow holes, and the like is two or four or more, respectively, depending on the number of blades.

  Further, in the drill bit A of the embodiment, as shown in FIGS. 2 and 3, the discharge groove surfaces 13 b 1 to 13 b 3 are formed to be inclined obliquely forward and the blow hole 13 b 12 is inclined obliquely rearward. However, in the present invention, the inclination angles of the three blow holes 13b12 to 13b32 are arbitrary, and all of them may be inclined obliquely forward or all obliquely backward. Of course, it is also possible that only one blow hole is inclined obliquely backward.

  In the perforated bit A of the present embodiment described above, a so-called house-shaped bit in which a plurality of double-edged blade bodies 2a to 2c and 2a 'to 2c' are provided on the base metal 1 has been described as an example. However, the present invention is not limited to this. For example, it may be applied to a button-type bit in which a plurality of so-called button-type chips 3 are provided on the base 1 like a perforated bit A ′ shown in FIG.

  Further, like the perforation bit A ″ shown in FIG. 7, each guide surface 13a1 ′ to 13a3 ′ protrudes toward the rotation direction α of the perforation bit B in the rotation direction α, and the tip portion is 90 degrees or less. Of course, it is also possible to provide acute-angle strips 13a11 ′ to 13a31 ′ that form an acute angle, in this way, on the rotation direction α side of the perforation bit B on each guide surface 13a1 ′ to 13a3 ′, toward the rotation direction α. When the sharp bit portions 13a11 ′ to 13a31 ′ projecting and the tip portion having an acute angle of 90 degrees or less are provided, when the drill bit B rotates in the rotation direction α, the sharp bit portions 13a11 ′ to 13a31 ′ that rotate are perforated. Since it becomes possible to collect the slime of the time, the slime discharge property can be further improved.

A, A ', A "Drilling bit B Lock bolt 1 Base 11 Connecting surface 11a Connecting hole 12 Tip holding surface 121 Blade body holding seat 13 Outer peripheral side surface 13a1-13a3, 13a1'-13a3' Guide surface 13a11'-13a31 ' Acute corner strips 13b1 to 13b3, 13b1 'to 13b3' Discharge groove surface 13b11 to 13b31 Discharge groove 13b12 to 13b32 Blow hole 2a to 2c, 2a 'to 2c' Blade 3 Button-type chip

Claims (3)

A drill bit in which a plurality of chips are provided on a base metal, and a hole is drilled by impacting a drilling object by vibration in the front-rear direction while shifting the position where the plurality of chips hit by rotation,
The base metal is
The connecting surface to which the tip of rock drill or rock bolt is connected,
A chip holding surface on which a plurality of chips are arranged;
A plurality of guide surfaces having a peripheral side surface about the center of the drilling bit for maintaining straightness during drilling between the connecting surface and the chip holding surface, and the guides between the guide surfaces. An outer peripheral side surface formed of a plurality of discharge groove surfaces that form a discharge groove that is recessed from the surface and discharges slime generated during drilling,
Each of the plurality of guide surfaces is
While inclined from the tip holding surface to the connecting surface so as to approach the axis of the drill bit,
The portions of the plurality of discharge groove surfaces that are closest to the axis of the drill bit are respectively
The closer to the chip holding surface, the closer to the axis of the perforated bit , the taper is inclined without a step at a constant inclination angle and reaches the chip holding surface ,
The tip holding surface is formed with a blade holding seat for fixing a plurality of tips,
A perforation bit characterized in that only the end portion of the blade body holding seat portion on the counter-rotating direction side is located on a boundary line between the guide surface and the discharge groove surface . The perforated bit according to claim 1,
The base metal is further
A connection hole formed at the center of the drill bit from the connection surface toward the tip holding surface, and connected to a hollow tip such as the rock drill or rock bolt,
A plurality of blow holes that are branched from the connection holes toward the plurality of discharge groove surfaces, open at each of the plurality of discharge groove surfaces, and discharge compressed air;
Each of the plurality of blowholes is
Provided with an inclination with respect to the perpendicular to the discharge groove surface provided with each blow hole,
A piercing bit characterized by that. The punch bit according to claim 2,
Among the plurality of blowholes,
At least one blowhole
While being provided inclined to the chip holding surface side with respect to the perpendicular in the discharge groove surface provided with the blow hole,
Other blowholes
Provided inclined to the connecting surface side with respect to the perpendicular in the discharge groove surface provided with the blowhole,
A piercing bit characterized by that.

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