JP4462771B2 - Drilling bit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drilling bit to be applied to a bedrock, a gravel layer, and the like, and in particular, paying attention to a mounting hole provided on the outermost peripheral side of the bit head, a gauge function in a cemented carbide chip implanted in the mounting hole Is intended to be enhanced.
[0002]
[Prior art]
Conventionally, this type of drilling bit has a case in which the bit head has a substantially circular surface or a circular surface on the drilling direction side, and the former belongs to the former. Japanese Patent Laid-Open No. 5-149074 and the like have been disclosed as belonging to the latter, such as Japanese Patent Publication No. Hoku.
[0003]
The former impact bit is divided into a carbide tip on the outermost circumference side of the bit head and a carbide tip on the inner side of the bit, and the tip of the carbide tip on the outermost circumference side is separated from the bit head. A gauge function is provided by protruding from the outer peripheral surface.
[0004]
Further, the latter ring bit is configured such that an auxiliary tip having a gauge function is provided on the outer peripheral side of the bit head with respect to the carbide tip on the tip side.
[0005]
And the impact bit and ring bit mentioned above, the carbide tip on the perforation direction side, from the viewpoint of mounting strength, even in the outermost peripheral part, the mounting hole does not cut out the outer peripheral edge of the bit body, and the complete circular state Presents.
[0006]
[Problems to be solved by the invention]
However, in the above-described impact bit, in order for the tip portion of the carbide tip in the outermost peripheral portion to have a gauge function with respect to the hole diameter at the time of drilling, the amount of protrusion must be increased. As a result, there is a problem that the wear becomes larger than the cemented carbide tips arranged in other parts, and if it is not appropriate in terms of the number of implants, the amount of protrusion, etc., this causes a short life.
[0007]
In addition, the latter ring bit has an improved gage function due to the arrangement of the auxiliary tips, but if the number of auxiliary tips implanted is large, if the tip of the carbide tip wears out, it will reach the end of its life at this point. Has a problem.
[0008]
For this reason, in the present invention, in order to solve the above-mentioned problems, an effective gauge is applied to the carbide tip implanted in the carbide tip implanted in the outermost peripheral portion of the bit head. A function is added.
[0009]
[Means for Solving the Problems]
The present invention has been made in view of the above points, and a button-shaped carbide tip is implanted in a mounting hole provided on an end surface of the bit head in the drilling direction side, and the tip of the carbide tip is also provided. The part is improved on the premise of a drilling bit protruding from the bit head.
[0010]
That is, the mounting hole located on the outermost peripheral side of the bit head forms an opening angle θ by cutting out a part of the outer peripheral edge, and this opening angle θ is the center on the axial center line of the mounting hole. When the point O is used as a reference, it is set within a range of 45 ° ≦ θ ≦ 135 °. In addition, the carbide tip in the mounting hole having the opening angle θ has a part of the implanted portion protruding from the outer peripheral side surface of the bit head, and the protruding amount 艟 from the outer peripheral side surface of the bit head has a carbide tip. Is set within the range of 0.05D ≦ δ ≦ 0.3D. These ranges were selected primarily with respect to the gauge function and mounting stiffness of the carbide tip.
[0011]
In the drilling bit of the present invention, the carbide tip is preferably fixed by brazing in the mounting hole, and the drill bit of the present invention has an end surface of the bit head having an annular surface or substantially What forms a circular surface is an object.
[0012]
BACKGROUND OF THE INVENTION
The present invention relates to a drilling bit to be applied to a bedrock, a gravel layer, and the like, and in particular, paying attention to a mounting hole provided on the outermost peripheral side of the bit head, a gauge function in a cemented carbide chip implanted in the mounting hole Is intended to be enhanced.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the drilling bit according to the present invention will be described with reference to the drawings.
1 and 2 are a plan view and a front view showing a drilling bit 1 according to the present invention. The drilling bit 1 includes a bit head 2 and a body 3, and the bit head 2 has a substantially circular shape. On the end face 2a to be presented, a button-shaped carbide chip 4 is implanted in an outer peripheral portion and an inner portion. In the case shown in the drawing, a total of 8 pieces are arranged in a set of two at the outer peripheral portion, and four pieces are arranged at the inner portion.
[0014]
The tip 4a of the cemented carbide chip 4 protrudes from the end face 2a of the bit head 2. The shape of the cemented carbide chip 4 is a two-stage conical shape with the leading edge as shown in FIGS. Various things are applied. The cemented carbide tip 4 is drilled in the end face 2a of the bit head 2 and implanted in the mounting hole 5, and is usually fixed by press-fitting, brazing, or the like.
[0015]
Further, since the bit body 2 discharges excavation waste generated by the excavation action of the cemented carbide tip 4, for example, two cemented carbide chips 4 arranged in an intersection portion of the end surface 2a and the outer peripheral surface 2b are arranged. Are formed on the inner surface of the end face 2a, and air or water injection openings 8 and 9 communicated with a connecting hole (not shown) drilled from the rear of the body 3. Are formed respectively.
[0016]
The mounting hole 5 located at the outermost peripheral portion of the end face 2a of the bit head 2 is formed in the inclined surface portion in the figure, but the outer peripheral edge of the outer peripheral side surface 2b of the bit head 2 is Some are cut away. This is a consideration to improve the discharging performance of the drilling waste by adding a gauge function to the hole wall at the time of drilling in the carbide tip 4 in the mounting hole 5 and is necessary for implanting the carbide tip 4. In the outer peripheral portion having a certain constant width, a part of the outer peripheral edge is notched so that the diameter of the carbide tip 4 located at the outermost peripheral portion is larger than the diameter of the carbide tip 4 located at the other inner side. It also means that it can be set.
[0017]
3 and 4 are a plan view and a front view showing another embodiment of the drilling bit according to the present invention, which is applied to the ring bit 1 in which the end surface 2a of the bit head 2 has an annular surface shape. .
[0018]
The ring bit 1 is described with the same reference numerals given to the same parts as the above-described drilling bit 1, but in the illustrated case, the carbide tip 4 has an annular shape of the bit head 2. In the end surface 2a, the outer peripheral side and the inner peripheral side are divided at a ratio of 2: 1, and are implanted into the mounting holes 5 respectively drilled in the inclined surface portions toward the outer peripheral side and the inner peripheral side. Is fixed by press-fitting or brazing.
[0019]
Further, in order to facilitate the discharge of excavation waste generated by the action of the cemented carbide chip 4, the bit head 2 is formed with discharge grooves 10a, 10b, 10c composed of three parts.
[0020]
The ring bit 1 may incorporate other bits (not shown) on the inner peripheral side of the bit head 2, but when used alone, the ring bit 1 also has an inner peripheral side mounting hole 5. The inner peripheral edge may be partly cut out for the purpose described above.
[0021]
By the way, as shown in FIGS. 5 (a) (b) to 8 (a) (b), the mounting hole 5 located on the outermost peripheral side of the end face 2a of the bit head 2 is formed on the bit head 2. A part of the outer peripheral edge of the outer peripheral side surface 2b is cut away. As described above, this is a consideration for enhancing the gauge function for the hole wall during drilling.
FIGS. 5 (a) (b) to 8 (a) (b) show the combinations of the shape of the tip portion 4a of the cemented carbide tip 4, the inclination angle α of the end surface 2a, and the implantation angle β of the cemented carbide tip 4. It is explanatory drawing which showed.
[0022]
5 (a) and 5 (b), the tip of the carbide tip 4 has a slightly larger radius of curvature than the radius of curvature of the hemispherical surface (D / 2), and its tip is a flat surface. The inclination angle α at the end face 2a of the bit head 2 is set to 30 °, and the implantation angle β with respect to the axial line 11 of the carbide tip 4 with respect to the drilling direction of the bit head 2 is set to 30 °. It is. Further, the carbide chip 4 forms a protrusion amount δ with respect to the outer peripheral side surface 2b of the bit head 2 and forms an opening angle θ by partially cutting out the outer peripheral edge of the outer peripheral side surface 2b.
[0023]
On the other hand, in FIGS. 6 (a) and 6 (b), the tip portion of the cemented carbide tip 4 has a two-stage conical shape, and its tip is flat, and the inclination angle α is 15 °. The implantation angle β of the carbide tip 4 is set to 30 °. The carbide tip 4 is formed with a protruding amount δ with respect to the outer peripheral side surface 2b of the bit head 2 as described above, and a part of the outer peripheral edge of the outer peripheral side surface 2b is notched so that an opening angle is obtained. θ is formed.
[0024]
Further, in FIGS. 7 (a) and 7 (b), the tip portion of the cemented carbide tip 4 is a so-called tapered shape having a one-step cone shape, and its tip is flat, and the inclination angle α is 15 °. The implantation angle β of the carbide tip 4 is set to 0 °. The carbide tip 4 is formed with a protruding amount δ with respect to the outer peripheral portion 2a of the bit head 2 as described above, and the opening angle is obtained by partially cutting the outer peripheral edge of the outer peripheral side surface 2b. θ is formed. In the case of this embodiment, since the notched portion of the outer peripheral edge extends greatly in the axial direction, brazing is preferable in terms of strength.
[0025]
8 (a) and 8 (b), the tip of the carbide tip 4 has a hemispherical shape, the inclination angle α is 0 °, and the implantation angle β of the carbide tip 4 is 30 °. Is set. The carbide tip 4 is formed with a protruding amount δ with respect to the outer peripheral portion 2a of the bit head 2 as described above, and the opening angle is obtained by partially cutting the outer peripheral edge of the outer peripheral side surface 2b. θ is formed.
The drilling bit 1 configured in this manner is normally set within the range of 0 ° ≦ α ≦ 50 ° with respect to the inclination angle α described above, and normally with respect to the implantation angle β, 0 ° ≦ β ≦ 45 °. It is set within the range.
[0026]
Further, the mounting hole 5 located on the outermost peripheral side of the bit head 2 described above forms an opening angle θ by cutting out a part of the outer peripheral edge as described above.
[0027]
For example, referring to FIG. 5B, when the center point O of the axial center line 11 of the mounting hole 5 is used as a reference, the radial lines 12 and 13 are formed. This is an angle formed when the point O is connected to the notched end of the outer peripheral edge, and is set within a range of 45 ° ≦ θ ≦ 135 °. This is because if the opening angle θ is less than 45 °, the effect of the gauge function in the carbide tip 4 is small, and if the opening angle θ exceeds 135 °, the mounting strength of the carbide tip 4 is impaired.
[0028]
Further, the cemented carbide tip 4 in the mounting hole 5 having the opening angle θ has a protrusion amount δ from the outer peripheral side surface 2b, for example, as shown in FIG. When set as a reference, it is set within the range of 0.05 D ≦ δ ≦ 0.3D. This is because if the protrusion amount δ is less than 0.05D, the excavation of the excavated waste by the cemented carbide tip 4 becomes worse and the gauge function becomes smaller. On the other hand, if the protrusion amount δ exceeds 0.3D, the wear amount of the cemented carbide tip 4 increases, and the mounting strength also decreases, resulting in a problem.
[0029]
On the other hand, in the above-described conventional product, the notch of the mounting hole 5 is not considered at all, and thus the shaft center line 11 is inevitably brought closer to the inside of the bit head 2. As a result, in the conventional product, in order to ensure the above-described protrusion amount δ, the protrusion amount h1 from the end face 2a of the cemented carbide chip 4 must be increased, and on the contrary, by increasing the protrusion amount h1, The wear amount of the hard tip 4 is increased or broken.
[0030]
As for the protrusion amount h1 described above, according to Japanese Examined Patent Publication No. 63-5549, 0.6 to 1.0D is appropriate for the diameter D of the carbide tip 4. Therefore, the conventional drilling bit 1 has a configuration in which it is difficult to secure the protrusion amount δ within the range of the protrusion amount h1 described above. In short, in a normal conventional product, the carbide tip 4 in the outermost peripheral portion is configured to be difficult to add a gauge function.
[0031]
【The invention's effect】
In the present invention, as described above, the mounting hole 4 drilled on the outermost peripheral side of the end surface 2a of the bit head 2 is within a specific range by partially notching the outer peripheral edge of the bit head 2. The carbide tip 4 having an opening angle θ and being implanted in the mounting hole 4 having the opening angle θ forms a protrusion amount δ in a specific range with respect to the outer peripheral side surface 2b of the bit head 2. It is a thing.
[0032]
Therefore, in the drilling bit 1 of the present invention, the carbide chip 4 positioned on the outermost periphery side is added with a gauge function for the hole wall at the time of drilling. , It has the advantage that excavation waste is improved and excavation efficiency is improved.
[0033]
[Brief description of the drawings]
FIG. 1 is a plan view of a main part showing an embodiment of a drilling bit according to the present invention.
FIG. 2 is a front view with respect to FIG.
FIG. 3 is a plan view of a main part showing another embodiment of the bit for punching according to the present invention.
4 is a front view with respect to FIG. 4;
FIGS. 5A and 5B are explanatory views showing an implanted state located in the outermost peripheral portion of the bit head in one embodiment of the present invention, wherein FIG. 5A is an explanatory view from the front side, and FIG. It is explanatory drawing of.
FIGS. 6A and 6B are explanatory views showing an implanted state located at the outermost peripheral portion of the bit head in another embodiment of the drilling bit according to the present invention, where FIG. It is explanatory drawing from a direction.
FIGS. 7A and 7B are explanatory views showing an implanted state located at the outermost peripheral portion of the bit head in another embodiment of the drilling bit according to the present invention, where FIG. It is explanatory drawing from a direction.
FIGS. 8A and 8B are explanatory views showing an implanted state located at the outermost peripheral portion of the bit head in still another embodiment of the drilling bit of the present invention, where FIG. It is explanatory drawing from an upper direction.
[Explanation of symbols]
1 Drilling bit 2 Bit head
2a End face
2b Outer peripheral side 3 Body 4 Carbide tip
4a Tip
4b Implanted part 5 Mounting hole 6 Discharge groove 7 Discharge groove 8 Opening 9 Opening
10a Discharge groove
10b Discharge groove
10c Discharge groove
11 Axial line
12 radial lines
13 Radial line

Claims (3)

For the drilling, a button-shaped carbide tip is implanted in the mounting hole provided on the end face of the bit head in the drilling direction, and the tip of the carbide tip protrudes from the bit head. In bits
The mounting hole located on the outermost peripheral side of the bit head constitutes an opening angle ridge by cutting out a part of the outer peripheral edge, and this opening angle ridge is a center point O on the axial center line of the mounting hole. Is set within a range of 45 ° ≦ θ ≦ 135 °,
In addition, the cemented carbide tip in the mounting hole having the opening angle θ has a part of the implanted portion protruding from the outer peripheral side surface of the bit head, and the protruding amount δ from the outer peripheral side surface of the bit head is A drilling bit characterized by being set within a range of 0.05D ≦ δ ≦ 0.3D when the diameter D of the chip is used as a reference.  The drill bit according to claim 1, wherein the cemented carbide tip is fixed by brazing in the mounting hole.  The drilling bit according to claim 1 or 2, wherein an end surface of the bit head forms an annular surface or a substantially circular surface.

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