JP2012237148A - Drilling bit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drilling bit that ensures performance of discharging slime (drill powder) while ensuring an increased length of a guide surface in a circumferential direction to improve straight advance performance.SOLUTION: A drilling bit A is provided, in which a metal base 1 has a coupling surface 11 to which a tip of a rock drill, a rock bolt or the like is coupled; a blade body holding surface 12 on which a plurality of blade bodies 2a to 2c are arranged; and an outer peripheral side surface 13 formed of guide surfaces 13a1 to 13a3 for maintaining straight advance performance between the coupling surface 11 and the blade body holding surface 12 during drilling, and of discharge groove surfaces 13b1 to 13b3 recessed more than the guide surfaces 13a1 to 13a3, respectively, for discharging slime produced during drilling. On the blade body holding surface 12, the plurality of blade bodies 2a to 2c are arranged such that a circumferential length of the drilling bit A in a rotating direction α on each of the guide surfaces 13a1 to 13a3 is longer than the circumferential length of the drilling bit A in a counter-rotating direction β on each of the guide surfaces 13a1 to 13a3, on the basis of a position on which each of the blade bodies 2a to 2c is arranged.

Description

  The present invention is used, for example, by being attached to the tip of a rock drill, a rock bolt, or the like, and a plurality of blades (chips) called a so-called house shape (also called chisel shape) on the front end surface of the base metal. And a perforating bit that perforates by impacting the object to be perforated by vibration in the front-rear direction while shifting the position where the plurality of blades hit by rotation.

  A drill bit in which a base metal is provided with a plurality of blades made of a cemented carbide called a house shape is attached to the tip of, for example, a rock drill or a rock bolt, and the plurality of blades hit by rotation. Drilling is performed by giving an impact to the object to be drilled by vibration in the front-rear direction while shifting the position. In such a perforated bit, a plurality of cemented carbide blades are fixed to a blade holding part formed at the tip of a steel base by brazing, and a slime ( It is a basic form to form a discharge groove for (kuri powder) (for example, see Patent Documents 1 and 2). When a drill bit employing such a cemented carbide blade is mounted on the tip of a lock bolt and used, for example, the shaft center of the drill bit is approximately 10 times as many as several hundred revolutions per minute. Depending on the maximum outer diameter of the drilling bit, it oscillates in the front-rear direction, hits the drilled object such as rock, and discharges slime from the discharge groove toward the rear end of the lock bolt. Proceed by forming a long hole with a hole diameter.

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

  By the way, in order to improve the discharge of slime (chip powder) generated at the time of drilling as much as possible, the slime (chip powder) is discharged immediately from the side opposite to the rotation direction of the drill bit in each blade (chip). It is necessary to form a plurality of discharge groove surfaces that form the discharge grooves and to ensure a wide circumferential width of the discharge groove surfaces.

  However, if the circumferential width of the discharge groove surface is secured wide, the circumferential length of the base metal that becomes the guide surface in the drilling hole becomes small, and the straightness of the drill bit that vibrates in the front-rear direction due to vibration while rotating. Decreases.

  In particular, in a drill bit employing an expensive cemented carbide blade, the cost reduction effect increases as the number of cemented carbide blades (tips) decreases. When the number of blades is reduced in this way, the striking force is increased for hard rocks, but due to the small number of blades (chips), misalignment, that is, the rotation axis is likely to be displaced. For this reason, a straight-advancing guide function that the guide surface that is the outermost peripheral side surface of the base metal plays an important role, and it is necessary to ensure the length of the guide surface in the circumferential direction as much as possible.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a drill bit that secures a large length in the circumferential direction of the guide surface and improves straightness while ensuring the discharge of slime (dish flour).

In order to achieve the above object, the drill bit according to the present invention is provided with a plurality of blade bodies on a base metal, and impacts the object to be drilled by vibration in the front-rear direction while shifting the position where the plurality of blade bodies hit by rotation. A drilling bit for drilling by giving the base metal, a connecting surface to which the tip of the rock drill or rock bolt is connected, a blade holding surface on which a plurality of blades are disposed, A plurality of guide surfaces having a peripheral side surface about the center of the drill bit for maintaining straightness during drilling between the coupling surface and the blade holding surface, and the guides between the guide surfaces. An outer peripheral side surface formed of a plurality of discharge groove surfaces forming a discharge groove for discharging slime generated during drilling, and the blade body holding surface is a position where the plurality of blade bodies are provided. Centered on the perforation bit in the plurality of guide surfaces. Circumferential direction of the rotation direction of, to be longer than the circumferential length of the counter-rotation direction of the drilling bit in the guide surface, placing said plurality of blade body, a drilling bit, characterized in that.
This makes it possible to ensure the length of the guide surface in the circumferential direction while ensuring the discharge of slime (chip powder), and improve the straightness of the drill bit.
Further, the blade holding surface is a plane perpendicular to the axial center direction of the drill bit, and a plurality of blades are fitted into the recessed portion on the flat blade holding surface and fixed by brazing. A blade holding seat portion is formed, and an end portion of the blade holding seat portion on the counter-rotation direction side of the drilling bit includes the guide surface on the counter-rotation direction side of the drill bit and the discharge groove surface. It may be located on the boundary line.
In this case, the discharge groove starts immediately from the end of the blade holding seat portion on the counter-rotating direction side of the perforating bit, so that it is possible to further improve the discharge of slime. .
Moreover, you may make it provide the acute-angle strip part which protrudes toward the rotation direction of the said perforation bit in each said guide surface, and makes the front-end | tip part makes an acute angle of 90 degrees or less.
In such a case, the slime (drilling powder) at the time of drilling can be collected by the rotating acute-angled strip portion, so that the discharge of slime (drilled powder) can be further improved.
Moreover, you may make it the said some blade body be a shape where the longitudinal direction center of the blade edge | tip protruded ahead circularly.
In such a case, since it becomes possible to relieve stress applied to the plurality of blades at the time of impact, it is possible to extend the life of the plurality of blades and also reduce the burden during drilling work. It becomes possible.

  In the drill bit of the present invention, the rotation direction of the drill bit on the guide surface with reference to an extension line extending in the connecting surface direction in parallel with the axial direction of the drill bit from the tip of the outermost cutting edge of the plurality of blade bodies The circumferential length of the drilling bit is longer than the circumferential length of the perforating bit in the counter-rotating direction on the guide surface, that is, each blade body is shifted in the counter-rotating direction. Slime (kurimu) that has moved the body in the counter-rotating direction is likely to enter a discharge groove that exists nearby. This makes it possible to ensure the length of the guide surface in the circumferential direction while ensuring the discharge of slime (chip powder), and improve the straightness of the drill bit.

(A), (b) is the top view and II sectional view taken on the line of the punching bit of Embodiment 1, respectively. FIGS. 2A and 2B are a left side view and a right side view, respectively, of the drill bit according to the first embodiment shown in FIG. It is a figure which shows the state which connected the lock bolt to the piercing | piercing bit of Embodiment 1, and is drilling as a self-piercing | locking lock bolt. (A), (b) is a top view which shows the other example of the punching bit of Embodiment 1, respectively. (A), (b) is the top view and front view of a drilling bit of Embodiment 2 of this invention, respectively. (A), (b) is a top view which shows the other example of the punching bit of Embodiment 2, respectively. FIG. 6 is a front view of a drill bit according to a third embodiment.

  Hereinafter, Embodiments 1 to 3 of the perforated bit according to the present invention will be described in detail with reference to the accompanying drawings.

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

  The drill bit A according to the first embodiment is attached to the tip of a rock drill or a self-drilling lock bolt, for example, and is shown in FIGS. 1 (a) and 1 (b) and FIGS. 2 (a) and 2 (b). As described above, the base 1 is provided with a plurality of blade bodies 2a to 2c (in the present embodiment, for example, three for convenience) provided as so-called house-shaped chips, and a position where the plurality of blade bodies 2a to 2c hit by rotation. This is a drill bit that performs drilling by giving impact to a drilling target object such as hard rock or soft rock by the vibration in the front-rear direction while shifting.

  Here, the number of rotations of the perforation bit A is, for example, about 200 rotations per minute, the number of hits by vibration in the front-rear direction is about 1800 times per minute, which is nine times the number of rotations, By rotating the perforation bit A by 40 degrees by one hit, the position where the blades 2a to 2c hit is rotated, and one turn is made by nine hits.

  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 has a plurality of blades 2a to 2c on a connecting surface 11 to which a tip portion (not shown) such as a rock drill or a rock bolt is connected and a plane perpendicular to the axial direction of the drill bit A. A peripheral side surface with the center C of the perforation bit A as an axis is provided between the blade body holding surface 12 on which the blade is disposed, and the connecting surface 11 and the blade body holding surface 12 in order to maintain straightness during drilling (drilling). The outer circumference provided with a plurality of guide surfaces 13a1 to 13a3 and discharge groove surfaces 13b1 to 13b3 that are recessed from the guide surfaces 13a1 to 13a3 and form a plurality of discharge grooves 13b11 to 13b31 for discharging slime generated during drilling. And a side surface 13.

  As shown in FIG. 1B, the connecting surface 11 has a rock drill rod having a hollow hole (not shown) for sending compressed air and a tip of a rock bolt made of a hollow rod (not shown). A connecting hole 11a such as a screw hole 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 blade body 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 and 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.

  In the blade holding surface 12 of the first embodiment, the plurality of blades 2a to 2c are rotated in the rotation direction α of the perforation bit A on the guide surfaces 13a1 to 13a3 with the arrangement position of the blades 2a to 2c as a base point. Is arranged so that the circumferential length is longer than the circumferential length in the counter-rotating direction β of the drill bit A on the guide surfaces 13a1 to 13a3. In other words, in other words, the plurality of blade bodies 2a to 2c are shifted to the blade body holding surface 12 from the center position in the circumferential direction of the guide surfaces 13a1 to 13a3 toward the anti-rotation direction β side of the drill bit. Each of the positions is disposed and fixed by brazing.

  For example, in the case of the blade body 2b, as shown in FIG. 2 (b), the guide is based on an extension line 13a2CL extending from the outermost tip of the blade body 2b in parallel with the axial direction of the drill bit A as a reference. The circumferential length 13a2L1 in the rotational direction α of the perforating bit A on the surface 13a2 is arranged on the blade body holding surface 12 so as to be longer than the circumferential length 13a2L2 in the counter-rotating direction β of the perforating bit A on the guide surface 13a2. ing. 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 (chip powder) that has moved the blades 2a to 2c in the counter-rotating direction β along with the rotation is present in the vicinity of 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 discharge of slime (chip powder), and the straightness of the drill bit A can be improved.

  Further, in the drilling bit A of the first embodiment, the end portions 121a1 to 121c1 of the blade holding seat 121 on the anti-rotation direction β side of the drilling bit A are connected to the guide surface 13a1 on the anti-rotation direction β side of the drilling bit A. To 13a3 and the discharge groove surfaces 13b1 to 13b3.

  Therefore, in the drill bit A according to the first embodiment, even when the circumferential length of the drill bit A in the rotation direction of the guide surfaces 13a1 to 13a3 is secured in order to ensure the straightness of the drill bit A, the blade body holding seat 121 is provided. Since the discharge groove surfaces 13b1 to 13b3 start immediately from the end portions 121a1 to 121c1 on the counter-rotating direction β side of the perforating bit A in FIG. Can be improved in the discharge of slime (steamed powder) that moves in the counter-rotating direction β.

  Further, as shown in FIG. 2B, blow holes 13 b 12 formed on the discharge groove surfaces 13 b 1 to 13 b 3 of the drill bit A according to the first embodiment are inclined in the traveling direction, that is, in the direction of the blade holding surface 12. And blow holes 13b22 and 13b32 formed to be inclined in the retreat direction opposite to the traveling direction, that is, in the direction of the connecting surface 11. Therefore, since the compressed air for discharging slime is discharged from the three blow holes 13b12 to 13b32 in the retreating direction opposite to the traveling direction, the slime is coupled with the rotation of the perforating bit A. Can be effectively discharged.

  FIG. 3 is a view showing a state in which drilling is performed in the form of a self-drilling lock bolt formed by connecting a lock bolt B to the drill bit A of the first embodiment.

  As shown in FIG. 3, in the perforated bit A of Embodiment 1, the shape of the outer peripheral side surface 13 of the base metal 1 becomes narrower from the blade body holding surface 12 on the front end side toward the connecting surface 11 side on the rear end side. When the self-drilling lock bolt is to be pulled back as compared with the metal base plate in which the step perpendicular to the axial direction of the drill bit A is formed. In this case, the slime can easily move 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 the operability (workability) is improved.

  In the perforation bit A according to the first embodiment, three blade bodies 2a to 2c are provided on the blade body holding seat portion 121. However, the present invention is not limited to this. Of course, four or more may be provided. This also applies to other embodiments described later.

  Moreover, in the drill bit A of Embodiment 1, as shown to Fig.1 (a), on the blade holding seat part 121, with respect to the center C of the said drill bit A, several blade body 2a- The center side of 2c is arranged separately and fixed, but the present invention is not limited to this, and as shown in FIG. 4 (a), the gaps on the center side of the current blades 2a to 2c are further provided. The blade body 2d may be further added so as to fill the (space), or a plurality of blade bodies 2a to 2c longer than the plurality of blade bodies 2a to 2c shown in FIG. Needless to say, the blades 2a ′ to 2c ′ may exist up to the position of the center C by using the blades 2a ′ to 2c ′. In such a case, the gap (space) on the center side of the current blade bodies 2a to 2c is also filled with the blade body 2d made of a cemented carbide such as tungsten carbide. Therefore, rather than the drill bit A shown in FIG. The piercing capability in the center C portion of the piercing bit A can be improved. 4A, the blade body 2d uses the same material and the same size as the blade bodies 2a to 2c, and the blade bodies 2a to 2d used in the drill bit A shown in FIG. Since the same blade body as 2c can be used, there is also an advantage that the manufacturing is easier than that shown in FIG.

  Further, in the drill bit A of Embodiment 1, as shown in FIGS. 2A and 2B, blow holes 13b12 formed in the discharge groove surfaces 13b1 to 13b3 so as to be inclined in the traveling direction, and the traveling direction, Has been described as having blow holes 13b22 and 13b32 formed in the opposite directions, but in the present invention, the inclination angles of the three blow holes 13b12 to 13b32 are arbitrary, and all are inclined in the traveling direction. Alternatively, they may all be inclined in the direction opposite to the traveling direction, or may be inclined in the direction opposite to the traveling direction.

Embodiment 2. FIG.
Next, the piercing bit A ′ according to the second embodiment of the present invention will be described.

  FIGS. 5A and 5B are a plan view and a front view, respectively, of the drill bit A ′ according to the second embodiment of the present invention.

  As shown in FIGS. 5 (a) and 5 (b), in the piercing bit A ′ of the second embodiment, on the rotation direction α side of the piercing bit A ′ on each guide surface 13a1 ′ to 13a3 ′, in the rotation direction α. It is characterized by providing acute-angle strips 13a11 ′ to 13a31 ′ that protrude toward the top and have an acute angle of 90 degrees or less at the tip. Each of the guide surfaces 13a1 'to 13a3' has a peripheral side surface about the center C of the drill bit A 'of the second embodiment. Since the other configuration is the same as that of the puncturing bit A ′ of the first embodiment shown in FIG.

  In the drilling bit A ′ of the second embodiment, the counter-rotation direction β side of the drilling bit A ′ on each guide surface 13a1 ′ to 13a3 ′ is configured in the same manner as the drilling bit A ′ of the first embodiment. Yes.

  Therefore, in the drilling bit A ′ of the second embodiment, the shapes of the plurality of discharge groove surfaces 13b1 ′ to 13b3 ′ formed between the guide surfaces 13a1 ′ to 13a3 ′ are the same on the guide surfaces 13a1 ′ to 13a3 ′. By providing the acute angle strips 13a11 ′ to 13a31 ′ projecting in the rotation direction α on the rotation direction α side of the perforated bit A ′, as shown in FIG. A left-right asymmetric curved surface that is warped with the acute-angled strips 13a11 ′ to 13a31 ′ having a hook shape as a tip is formed.

  Therefore, according to the perforated bit A ′ of the second embodiment, as in the case of the perforated bit A ′ of the first embodiment, the circumferential direction of the guide surfaces 13 a 1 ′ to 13 a 3 ′ is ensured while ensuring the discharge of slime. The length can be secured, the straightness of the drill bit A ′ can be improved, and the edge 121 a 1 to 121 c 1 of the blade holding seat 121 on the side β in the counter-rotating direction of the drill bit A ′. Since the discharge groove surfaces 13b1 ′ to 13b3 ′ are started, it is possible to improve the discharge performance of the slime (chip powder) pulverized by striking the plurality of blade bodies 2a to 2c.

  In particular, in the drilling bit A ′ of the second embodiment, the guide bits 13a1 ′ to 13a3 ′ project toward the rotation direction α of the drilling bit A ′ on the guide surfaces 13a1 ′ to 13a3 ′, and the tip portion is 90 degrees or less. Since the acute-angle strip portions 13a11 ′ to 13a31 ′ forming an acute angle are provided, when the drill bit A ′ rotates in the rotation direction α, the slime (chip powder) at the time of drilling is collected by the rotating acute-angle strip portions 13a11 ′ to 13a31 ′. Since it becomes possible, the discharge | emission property of slime (kow flour) can be improved more.

  In the perforated bit A ′ of the second embodiment, as shown in FIG. 5A, the shapes of the discharge groove surfaces 13b1 ′ to 13b3 ′ formed between the guide surfaces 13a1 ′ to 13a3 ′ are right and left. Although the present invention has been described so as to form an asymmetric curved surface, the present invention is not limited to this. For example, as shown in FIG. 6A, the rotation of the perforation bit A ′ on each guide surface 13a1 ′ to 13a3 ′. Needless to say, acute angle strips 13a11 "to 13a31" having a triangular cross section that protrudes toward the rotational direction α and has an acute angle of 90 degrees or less are provided on the direction α side.

  Moreover, also in the drilling bit A ′ of the second embodiment, as shown in FIG. 6B, a plurality of blade bodies 2a ′ to 2c ′ longer than the plurality of blade bodies 2a to 2c shown in FIG. Of course, a plurality of blades 2a 'to 2c may be present up to the center.

Embodiment 3. FIG.
Next, the punch bit A ″ according to the third embodiment of the present invention will be described.

  FIG. 7 is a front view of the drill bit A ″ according to the third embodiment.

  In the plurality of blades 2a to 2c and 2a 'to 2c' of the drilling bits A and A 'of the first and second embodiments, as described with reference to Figs. In the drilling bit A ″ 3, as shown in FIG. 7, the cutting edges of the plurality of blade bodies 2 a ″ to 2 c ″ are formed in a circular arc shape, that is, the longitudinal center of the cutting edge protrudes forward in an arc shape. The configuration other than the point in which the longitudinal center of the cutting edges of the plurality of blade bodies 2a ″ to 2c ″ protrudes forward in an arc shape is the same as the drill bits A and A ′ of the first and second embodiments. Since they are the same, the same components are denoted by the same reference numerals and description thereof is omitted.

  For this reason, in the drilling bit A ″ of the third embodiment, the guide surfaces 13a1 ′ to 13a3 ′ are secured while ensuring the discharge of slime, as in the drilling bits A and A ′ of the first and second embodiments. Can be secured, the straightness of the drill bit A ″ can be improved, and the end of the drill bit A ″ in the counter-rotating direction β side of the blade holding seat 121 can be improved. Since the discharge groove surfaces 13b1 to 13b3 start from 121a1 to 121c1, it is possible to improve the discharge performance of the slime (chip powder) pulverized by hitting the plurality of blades 2a to 2c.

  In particular, in the drilling bit A ″ of the third embodiment, as shown in FIG. 7, the plurality of blade bodies 2a ″ to 2c ″ are configured to have a shape in which the longitudinal center of the blade edge protrudes forward in an arc shape. It is possible to relieve stress applied to the plurality of blades 2a "to 2c" at the time of hitting with the bit A ", thereby extending the life of the plurality of blades and reducing the burden during drilling operations. Is possible.

A, A ', A "Drilling bit B Lock bolt 1 Base 11 Connection surface 11a Connection hole 12 Blade body holding surface 121 Blade body holding seat 13 Outer peripheral side surface 13a1-13a3, 13a1'-13a3' Guide surface 13a11'-13a31 ', 13a11 "to 13a31" Sharp corners 13b1 to 13b3 Discharge groove surface 13b11 to 13b31 Discharge groove 13b12 to 13b32 Blow hole 2a to 2c, 2d, 2a' to 2c ', 2a "to 2c" Blade

Claims (4)

A drill bit in which a plurality of blades 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 blades hit by rotation,
The base metal is
A connecting surface to which the tip of the rock drill or rock bolt is connected;
A blade holding surface on which a plurality of blades are disposed;
Between the connecting surface and the blade body holding surface, a plurality of guide surfaces having peripheral side surfaces around the center of the drill bit for maintaining straightness during drilling, and the guide surfaces 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 guide surface and discharges slime generated during drilling,
The blade holding surface is
Centering on the position where the plurality of blades are provided, the circumferential length of the plurality of guide surfaces in the rotation direction of the drilling bit is longer than the circumferential length of the guide surface in the counter-rotation direction of the drilling bit. So as to arrange the plurality of blades,
A piercing bit characterized by that. The perforated bit according to claim 1,
The blade holding surface is
It consists of a plane perpendicular to the axial direction of the drill bit,
A blade body holding seat portion is formed on the blade holding surface of the planar shape, and a plurality of blade bodies are fitted into the recessed portion and fixed by brazing,
The counter-rotation direction end of the drill bit in the blade holding seat is located on a boundary line between the guide surface and the discharge groove surface on the counter-rotation direction side of the drill bit.
A piercing bit characterized by that. The punch bit according to claim 1 or 2,
Provided on the rotation direction side of the perforated bit in each guide surface is an acute-angle ridge that protrudes in the rotation direction and the tip of which forms an acute angle of 90 degrees or less.
A piercing bit characterized by that. In the drill bit according to any one of claims 1 to 3,
The plurality of blades are:
The center of the cutting edge in the longitudinal direction is a shape protruding in an arc shape forward,
A piercing bit characterized by that.

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