JP3047240U - Drilling inserts and drill bits - Google Patents

Abstract

(57) [Summary] In a drilling bit used for an earth auger or the like, a hardened state of a tip from a hard alloy at the tip of a shank is strengthened. In a chip (3) integrally fixed by inserting a part of the tip into a shank (2), an indentation (4) of the tip (3) is provided with irregularities for mutual coupling with the shank (2). Are formed by through holes 9 penetrating through. The shank 2 is formed by accommodating the chip 3 at a predetermined position of the mold and then casting the molten steel 2a, 2b. [Effect] The cast molten steel 2a, 2b enters the through holes 9 to maintain high integrity between the tip 3 and the shank 2.

Description

[Detailed description of the invention]

[0001]

[Technical field to which the invention belongs]

 The present invention belongs to the technical field of construction and civil engineering machines, and more particularly, to a drilling tip made of a hard alloy and a drilling bit using the same at a working tip for performing a predetermined operation of various machines.

[0002]

[Prior art]

 In the above-mentioned machine, for example, a bit at the tip for actually piercing or cutting a rock is formed by integrally fixing a tip to a tip of a shank made of structural carbon steel or the like. Brazing is often used to secure the tip to the shank.

[0003] However, in the case of brazing, it is necessary to polish a flat joint surface before brazing, which is troublesome and expensive. In addition, in the case of brazing, no matter how finely finished, the brazing melts at around 700 ° C. Therefore, due to the load applied during the work, there is no brazing strength, and the chip cannot be used during the work. Often they dropped out unexpectedly. For this reason, brazing is carried out with careful and highly sought-after techniques, and the above-mentioned difficulties and costs are only increasing. In particular, when the chip was formed of a sintered cemented carbide, the cost was very high because it was very expensive.

[0004]

[Problems to be solved and means for solving them]

 Therefore, an object of the present invention is to provide a drilling tip and a drilling bit which can extend the service life without accidental dropping of the tip during operation.

[0005] A means for that purpose is a drilling tip which is partially fixed to the tip of the shank and is integrally fixed, and performs mutual connection between the shank and the tip when fixed to the shank. The present invention is characterized in that the concave and convex portions are drilling tips formed in the entry portions.

[0006] In order to obtain an even stronger fixed state, it is preferable to form a retaining slope on the irregularities. Further, the formation of the irregularities may be performed by forming a through hole penetrating the entry portion.

[0007] According to another aspect of the present invention, there is provided a drill bit in which the drill chip according to any one of claims 1 to 3 is fixed to a tip of a shank. . Further, a drilling bit in which the drilling tip according to any one of claims 1 to 3 is fixed to a tip portion of a shank formed by casting molten steel may be used.

[0008]

[Action and effect]

 That is, according to the above-described configuration of the drilling tip, the unevenness formed in the entry portion that enters the shank in the fixed state is coupled to the shank so as to mesh with and interlace with the shank. Rather than relying solely on the adhesive strength on a flat surface, a strong locking force is created by the engagement. For this reason, the drilling tip can withstand the load during the work and does not come off unexpectedly and has a good fixed state.

In addition, when the retaining slope is formed in the unevenness as in claim 2, even if a force in the punching direction acts on the drilling tip, the unevenness is prevented by the unevenness. Power is born. For this reason, a strong holding force for holding the mutual connection is obtained, and further improvement in fixing strength can be expected.

The same applies to the case where the irregularities are formed by through holes as in claim 3. For example, the connection with the shank is performed when the shank is cast so that the molten steel enters the through holes. Thus, a structure that performs the same function as the above-mentioned retaining slope can be automatically formed, and a strong holding force for maintaining mutual connection can be obtained.

According to the configuration of the drilling bit described above, the drilling tip and the shank are fixed in a state in which the concave and convex portions are connected to each other, so that only the adhesive force in a flat surface by brazing as in the related art is used. Unlike this, a high locking force is generated by the connection. For this reason, the fixed state of the drilling tip can be made to withstand the inability to perform during work, and a drilling bit can be obtained in which the drilling tip does not accidentally come off.

[0012] Furthermore, it is possible to simultaneously form the shank and connect the chip to the chip, instead of joining the separately formed shank to the chip by brazing as in the related art. In this case, the work of integration by brazing is not required, and precise polishing of the joint surface required for brazing is not required, so that labor and cost can be reduced. Also, since it is not necessary to separately form the shank, the shank forming cost can be reduced. Furthermore, since it is not brazed, it can withstand high temperatures, and in addition to the above-described strong integrity, a more favorable fixed state can be obtained.

According to a fifth aspect of the present invention, the shank is formed by casting, and when the shank is integrated with the drilling tip at the time of forming, the shank can be simply cast without requiring other members. Can be fixed. Moreover, the fixed state is strong as described above.

[0014]

【Example】

 One embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a perspective view showing an earth auger bit 1 as an example of a drill bit 1 (hereinafter, referred to as a bit) used for an excavator, a rock drill, and the like. The bit 1 is integrally fixed with a part of the drilling tip 3 (hereinafter referred to as “tip”) inserted into the tip of the shank 2. There are various shapes of the bit 1 and the chip 3, and the illustrated one is an example.

The shank 2 is formed of structural carbon steel (SC material), and the tip 3 is formed of sintered cemented carbide. Except for the tip edge 5 protruding forward from the shank 2, that is, the above-described chip 3 in which the above-described entry portion 4 is formed in a rectangular plate shape, the upper surface 6, the lower surface 7, and the rear surface 8 have the shank 2. And is formed as shown in FIG.

That is, from the upper surface 6 to the lower surface 7 of the entry portion 4, a plurality of round through holes 9 penetrating the entry portion 4 are formed to form irregularities. The formation of the through holes 9 is performed at a soft stage after forming a predetermined shape in a pre-sintering stage. The arrangement and number of the through holes 9 shown in the drawing are examples. For example, the through holes 9 may be formed obliquely from the upper surface 6 to the rear surface 8 and from the lower surface 7 to the rear surface 8.

In manufacturing the bit 1, after forming the above-described chip 3, the following is performed. First, as shown in FIG. 3, a mold 11 having a cavity 10 corresponding to the shape of the bit 1 (see FIG. 1) is formed, and the chip 3 is stored and held at a predetermined position in the cavity 10 of the mold 11 ( (See FIG. 4). Since the specific gravity of the chip 3 is large, the mold 11 described above is preferably rigid. Thereafter, the molten steel 2a is cast into the cavity 10 to form the shank 2 (see FIG. 5). At this time, the cast molten steel 2 a enters the through hole 9 of the chip 3. For this reason, it is in a state where it is stopped by the molten steel 2b that has entered the through-hole 9, and is firmly integrated. Since the through-hole 9 penetrates through the entry portion 4 of the chip 3, both ends of the molten steel 2b in the through-hole 9 are strongly integrated with the molten steel 2a on the main body side of the shank 2, and the retaining action is high.

After that, the formed shank 2 is subjected to an annealing treatment. Before that, the chip 3 is coated with, for example, a ceramic paint to form an antioxidant film (not shown). . This is to prevent the properties of the chip 3 from deteriorating due to annealing.

In the chip 3 configured as described above, in the fixed state, the concave and convex portions formed in the entry portion 4 that enters the shank 2 are connected to the shank 2 so as to mesh with and entangle with the shank 2. Different from relying only on the adhesive strength in the plane by brazing as in the above, a strong locking force is generated by meshing. For this reason, it is possible to endure the load during the operation, and to obtain a good fixed chip that does not come off unexpectedly. In addition, since the unevenness is formed by the through holes 9, it also has a retaining function, and a strong holding force for maintaining mutual connection is obtained.

When the bit 1 is formed using such a chip 3, instead of joining the shank separately formed with the chip 3 as in the related art, the shank 2 is formed as described above. Coupling with the chip 3 can be performed simultaneously. In other words, the work of unifying by brazing is unnecessary, and precise polishing of the joint surface required for brazing is not required, so that labor and cost can be reduced. Further, since there is no need to separately form the shank 2, the molding cost of the shank 2 can be reduced. Furthermore, since it is not brazed, it can withstand high temperatures, and in addition to the above-described strong integrity, a more favorable fixed state can be obtained.

FIGS. 6 to 8 show a chip 3 according to another example. In the chip 3 shown in FIG. 6, round holes 12, 13, 14, 15, and 16 that do not penetrate the entry portion 4 are formed on the upper surface 6, the lower surface 7, and the rear surface 8 of the entry portion 4 so as to be uneven. . As shown in the cross-sectional view of FIG. 7, the unevenness formed by the round holes 12, 13, 14, and 15 formed on the upper surface 6 and the lower surface 7 has a retaining gradient to make it difficult to separate from the shank 2. ing. That is, two round holes 16 are formed in the rear surface 8 and perpendicular to the surface, while five round holes 12 are formed obliquely from the surface. Moreover, the front round holes 12, 12 and the rear round holes 13 are formed so as to be inclined in different directions from each other, in this case, the tip sides of the round holes 12, 13 are separated from each other. The same applies to the circular holes 14 and 15 formed in the lower surface 7. In addition, it may be formed to be inclined in a direction approaching each other, or may be formed by a square hole instead of a round hole.

FIG. 8 shows the chip 3 formed with protrusions 17... Unlike the case of sintered cemented carbide, this tip 3 is made of high chromium steel and formed by casting. In other words, at the time of casting, the rebar 17a or the like serving as the projection 17 may be held in such a manner as to protrude from the upper surface 6, the lower surface 7, and the rear surface 8 of the entry portion 4, and then cast into a mold (not shown). In the case where the reinforcing bar 17a is used as the projection 17 as shown in the drawing, the projection 17 is projected in three directions. Also contribute to the formation of the retaining gradient.

When the shank 2 is formed by casting and integrated as described above using these chips 3, since the unevenness has a retaining slope, the force in the punching direction acts on the chip 3. Even so, resistance is created to prevent the irregularities. For this reason, a strong holding force for holding the mutual connection is obtained.

[Submission date] October 17, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0014

[Correction method] Change

[Correction contents]

[0014]

【Example】

One embodiment of the present invention will be described in detail below with reference to the drawings. Figure 1 is a perspective view showing a bit 1 of the example of穿削bit 1 for use in drilling machines and drilling machines and the like (hereinafter, referred to as bits). The bit 1 is integrally fixed with a part (entry portion 4) of a drilling tip 3 (hereinafter referred to as a tip) inserted into the tip of a shank 2. There are various shapes of the bit 1 and the chip 3, and the illustrated one is an example.

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Change

[Correction contents]

When the shank 2 is formed by casting using these chips 3 and integrated as described above, since the unevenness has a retaining slope, a force in the punching direction acts on the chip 3. Even so, resistance is created to prevent the irregularities. For this reason, a strong holding force for holding the mutual connection is obtained. In the above description, only bits having one chip are shown, but it goes without saying that the same applies to bits in which a plurality of chips are arranged in a comb shape.

[Brief description of the drawings]

FIG. 1 is a perspective view of a drill bit.

FIG. 2 is a perspective view of a drill bit.

FIG. 3 is a cross-sectional view of a mold for explaining a bit manufacturing process.

FIG. 4 is a cross-sectional view illustrating a bit manufacturing process in a state where a chip is stored and held.

FIG. 5 is a cross-sectional view of a state where a shank is formed, for explaining a bit manufacturing process.

FIG. 6 is a perspective view of a chip according to another example.

FIG. 7 is a longitudinal sectional view of FIG. 6;

FIG. 8 is a perspective view of a chip according to another example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Bit for drilling 2 ... Shank 2a, 2b ... Molten steel 3 ... Tip for drilling 4 ... Entrance part 9 ... Through-hole 12-16 ... Round hole 17 ... Projection

Claims (5)

[Utility model registration claims] 1. A drilling tip which is fixed integrally with a tip of a shank by partially inserting the tip into a shank, wherein irregularities for mutually connecting the shank and the tip when fixed to the shank are provided. A drilling tip formed in the entry section. 2. The drilling tip according to claim 1, wherein the unevenness has a retaining slope. 3. The drilling chip according to claim 1, wherein the unevenness is formed by forming a through hole penetrating the entry portion. 4. A drill bit in which the drill tip according to any one of claims 1 to 3 is fixed to a tip of a shank. 5. A drilling bit in which the drilling tip according to any one of claims 1 to 3 is fixed to a tip of a shank formed by casting molten steel.