JPH10140960A - Boring bit for drifter drill - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve boring work efficiency for hard earth by the use of a rock drilling machine by providing a slit in a base metal of a bit for use in the rock drilling machine and embedding a cutting chip in the slit. SOLUTION: A slit center to equally divided a flat surface at the tip of a bit base metal 1 for drilling into three parts is provided, and a deviation E is set so that internal stresses, which is anticipated, may not be concentrated at the center to prevent fatigue failure of a weight rope such as an intermediate rod. And an eccentric angle θ1 is set so that the slit center, on the side of a bore wall, can first cut in the rotational direction thereof. The deviation E is, for example, 3-5mm and the eccentric angle θ1 is 3-5 degrees. And a slit 3 is provided in the metal 1 to embed a hard metal chip 2 in the slit 3 so as to be brazed using silver alloy. Thus boring work efficiency for hard earth using a rock drilling machine can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a drilling bit of the present invention which is attached to a rock drill at the time of drilling a hard soil or the like in which soft rocks or boulders are interposed. The present invention relates to an improvement in a drill bit in which the durability of weight steel tools such as a shank rod is remarkably improved.

[0002]

2. Description of the Related Art In recent years, there have been many works requiring drilling work such as a rock bolt method and an anchor method, and examples of drilling work on hard soil and the like are increasing. A drilling machine (rotary drill) using a rotary cutting mechanism is generally used for drilling in such hard soil and the like, and a cutting method using strong rotating force and thrust is adopted. Since this cutting method requires a strong reaction force, it is eventually mounted on a large base machine, while its weight and space are required for rock bolting, anchoring, and other drilling work at small construction sites. It is almost impossible to adopt it due to restrictions. In addition, in this cutting method, it is generally difficult to drill when encountering heterogeneous soft rock or boulders, so it is difficult to select drilling work in a place where geology changes.

Conventionally, for this purpose, a rock drill was used to make use of a cross bit or button bit for drilling hard rock, and a rock bolt hole or an anchor hole was drilled. However, when these bits are used, the blow holes frequently become clogged during drilling, and each time, the bits need to be removed and cleaned, or a time loss requiring replacement is required. Furthermore, when these bits are used for drilling hard earth, the cutting edge of the bit is driven into the hole, impeding rotation, and opposing stress acts on the bit, often causing breakage of the rod and the shank rod of the rock drill body. did. In the case of downward drilling, it is often difficult to collect or impossible to collect = abandoned → repeated, and conversely,
When a breakage accident occurred while drilling upward (for example, in a tunnel arch), the vehicle fell and did not matter in any direction, creating a state extremely dangerous to rock drills and human lives.

[0004]

DISCLOSURE OF THE INVENTION The present invention newly devises a bit for hard rock, which is mainly driven by a rock drill, and a base metal structure for improving a tip portion and holding a cutting edge, and by combining these, a cutting main body and an auxiliary impact are provided. It is an object of the present invention to provide an excellent method for improving the drilling efficiency of a hard rock or the like by a rock drill and improving the durability of a weight steel tool such as a rod.

Conventionally, drilling of hard soil or the like, which has been concerned about work by a rock drilling machine, has no suitable cutting-type drilling bit that can be mounted on the machine. Work had to be done. The drilling and crushing mechanism for hard rock bits is characterized in that the impact of a rock drill hits the hard rock body with the bit cutting edge to cause crushing or the like, and the hole is pierced. There is no repulsion hardness enough to cause the phenomenon, the cutting edge is built up and rotation is poor, and because of the mechanism to rotate it further, the bit operates reversely and pushes up, the stress that wears down the perforated surface works, and the rod works correctly. A twisting phenomenon occurred because the rotation and thrust were pressed, and a striking force acted on the phenomenon, resulting in frequent breakage of the rod and the shank rod attached to the rock drill body. Therefore, if the shape of the bit for hard rock is changed to a shape mainly composed of a rotating body, cutting can be performed by rotation, and hard rocks such as boulders can be pierced because an auxiliary impact crushing mechanism works. I have reached. This is the first object of the present invention.

Next, it is a well-known fact that when a hard rock is drilled, the phenomenon of clogging of a blowhole is extremely small, but it is very difficult to avoid this phenomenon when drilling a fault crush zone or hard soil. When a bit with a hole at the tip is pressed against hard soil or the like and rotated, the hard soil or the like at the hole portion grows toward the inside (upward) of the hole and gradually tightens to finally close the hole. At this time, the length due to the same diameter becomes a problem. If the portion having the same diameter is short, there is a limit to the degree of compaction of the obstruction. If there is a side hole as well as a center hole, even if the center hole is closed, blow air is blown out from the side hole, making it difficult to confirm the state of the blockage. Furthermore, if the blockage of the center hole grows, it penetrates into the flushing hole with a slightly larger diameter, and in the worst case, grows and blocks up to the entire length of the starter rod. As a result, it is considered that a problem of sticking of the rod (at worst unrecoverable) may occur, and a method for solving these problems in a short time is required. This is the second object of the present invention.

[0007]

The most troublesome thing in perforation of hard soil or the like is blow clogging, but the next problem is breakage of weight steel tools such as rods. The reason for this is that, as mentioned in the previous section, the building by the impacter has a very poor crushing effect. Therefore, the present invention has solved the above-mentioned problem by cutting and crushing by a rotating main body which is the origin of drilling. Next, the rotary cutting bit of the existing rotary drill has a sticking type for holding the hard tip, and when it is used on a rock drill, the frequency of dropping and breakage of the blade tip when hitting is high, so it is easy to occur. One of the problems was solved by selecting a method of embedding and fixing the cutting die by providing a slit in the base of the bit to be used.

Next, it was examined how to clear the phenomenon of blow clogging, which is difficult to avoid. First, the blow clogging that occurred with one blow hole was detected quickly. Next, the blow hole of the bit body is usually provided with the same diameter from the end contact surface of the rod to the discharge portion, and it is thought that the diameter is slightly smaller than the diameter of the flushing hole and the pressure is not reduced. It was observed that there was no change in the wall of the hole, and once it started to close, it was gradually compacted with the help of a blow by a blow. It becomes extremely difficult to take out if it is clogged and hardened in a small hole, and it becomes more difficult as its length becomes longer.

Therefore, in order to change the hole diameter (hole wall) of the blowhole, the diameter is changed into three stages, and the wall on the supply side rear side loses the wall resistance when the solidified plug comes out of the center part, and suddenly loses its resistance. When the clogging is restored, a blow capacity is needed to blow off the remaining crushed pieces around the cutting surface. The central part following this respects the existing diameter, which is slightly smaller than the flushing hole, which takes into account the pressure drop of the blow. In order to allow air (or flushing water) to permeate the wall surface at that pressure, the closing length was made as short as possible. Further, at the leading end portion (blow discharge port) connected therewith, a hole was formed in order to delay penetration and consolidation of the obstruction and facilitate cracking of the obstruction when hit. Thus, a measure was taken to automatically recover the clogging of the blow hole by using the blow pressure of air or water.

[0010]

[Effects]

A) Regarding the operation and effect according to the present invention, special results are expected in terms of workability, efficiency, economic efficiency, etc. in drilling work of hard soil and the like with a rock drill, which has hardly been considered possible. Drilling work for soft soil and the like with a rock drill becomes easy, and the selection range of model selection is expanded.

B) The drilling bit according to the present invention makes it possible to negotiate extremely smoothly the drilling work of hard soil or the like, which has been difficult with the conventional rock drilling machine. The environment has also been greatly improved, and it will greatly contribute to improving the operating rate of auxiliary machinery and related equipment through automatic return.

C) Troubles due to burial, breakage, etc. of weight steel tools such as rods are reduced, and economic efficiency is remarkably improved.

[0013]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. A) Fixing method of cemented carbide tip (bit tip cutting edge) To fix the cemented carbide tip (2), a slit center that evenly divides the tip plane of the bit metallurgy (1) into three is provided to reduce the internal stress that is expected to occur. The deviation (E) was set so as not to concentrate on the center part, and consideration was given to prevent fatigue breakage of the weight steel tool such as the intermediate rod. In addition, the eccentric angle θ1 was set so that the hole center side could cut the slit center first in the rotation direction of the bit, and further, the buried deviation angle θ2 was set in consideration of smooth cutting of the cutting edge and reduction of rotation resistance at the time of hitting. .

Each value is such that the slit center deviation (E) is 3 to 5 mm and the center eccentric angle θ1 is 3 to 5 mm.
The embedding deviation angle θ2 is set to 0 to 3 degrees, a slit (3) is provided in the base metal (1), and a cemented carbide chip is embedded in the slit and bonded (4) with silver wax.

The cutting depth of the bit is the difference (e) between the cutting edge of the carbide insert and the position of the tip (discharge port) of the blow hole. Therefore, the burial height (H1) and (H2) of the carbide tip
Is set based on the cutting depth in consideration of the bit gauge, the type and existence state of the target rock body to be drilled, the condition of the rock drill, the shape of the carbide tip, and the like. Therefore, the cutting depth (e)
Is 2 to 10 mm, and the buried height (that is, the depth of the slit)
Shall be determined. Since the height (H) of the cemented carbide tip varies depending on the above-mentioned considerations, it shall conform to the existing standard. The embedding height (H1) of the entire surface (cutting surface side) is selected by estimating the above-mentioned consideration conditions for drilling and the expected degree of discharge of the powder, but 25% to 50% of the height of the carbide tip.
And higher for soft rocks and lower for hard soils. The embedding depth (H2) on the back side is automatically determined from the height (H1) in order to shape according to the cutting edge angle of the carbide tip.

B) Shape of Carbide Tip (Bit Edge) The material and dimensions of a carbide tip can be generally changed depending on the size of the bit, the object to be drilled, and the like. Has been Except for the important part related to the operation and effect of the present invention, the existing optimum approximate shape and material are selected. The total length (Y) of the carbide tip is based on approximately 1/3 of the bit gauge, and its thickness ( T) is as thin as possible, the position of the cutout (X) is 25 to 30% of the total length (Y), and the bevel angle (θ) is 120 to 15
The angle (θ) was set to 55 to 60 degrees.

C) Number and Shape of Blow Holes Conventional bits for mounting a rock drill have many blow holes at two or more places, and are designed to take into account a decrease in the air pressure that is lifted by the flow velocity at the time of dust discharge. Conceivable. Furthermore, when encountering fault clay during drilling, in most cases, clogging of the hole occurs, and the rod cannot be closed and rotated.As a result, the intermediate rod is forced to adhere due to the driving phenomenon of poor blow and the fall of crushed pieces during discharge. You. Therefore, if the blowhole is located at one location, the discharge of the grinding powder is completely stopped, so that it is possible to immediately respond to the operation of the machine, and it is not necessary to spend time to recover the rotation or collect the bit and rod, and to fix the rod, etc. There is an advantage that you do not have to trouble.

Next, the shape of the blowhole passage will be described. In the conventional bit for mounting a rock drill, the overall blowhole length (LB) differs depending on the manufacturer, the type of the bit gauge and the type of the rod, and the diameter (d2) of the rod. Based on the diameter (d) of the existing flushing hole in the center,
It is manufactured at the ratio of the center part (d2).

The blowhole of the bit according to the present invention has its total length (LB) measured at the rear portion (d) based on the diameter (d).
1), the center (d2), and the tip (d3), the shape of which changes the diameter in three stages. The lengths corresponding to the respective diameters are (L1), (L2), and (L3). The standard diameter (d) of the flushing hole is usually in the range of 5 to 40 mm. D1 is 13 based on this diameter (d).
0 to 200%, d2 is 80 to 95%, d3 is 130 to 2
And the length L2 is 0.5 to 0.7 of d.
Times, L3 is 0.8 to 1.0 times, and L1 is LB− (L1 + L
2).

[0020]

According to the present invention, the conventional work form for drilling with a rock drill is not changed by installing the drill bit according to the present invention, and the work efficiency, the time efficiency, the economical efficiency of the weight steel tool for drilling, the working environment and the like are remarkable. An improved drilling technique has been obtained. When a conventional bit is mounted on a rock drill, drilling hard soil, etc., causes clogging of blowholes, and rods are frequently removed in order to recover the holes. Normally, a 10m hole that can be drilled at 1 hole / Hr is completed in one day. In some cases, however, when a hole was drilled with the bit of the present invention at an adjacent position, it was completed at 1 hole / Hr. Furthermore, the drilling of hard soil and the like was performed better by the conventional method of cutting mainly by rotation, and the result that the durability of weight steel tools for drilling such as bits, rods and shank rods was remarkably improved.

In a drilling operation using a rock drill, it is general that not only a rock drill but also a compressor, a water supply / drainage pump, a dust collector, a generator and other auxiliary machines are required during the working time. By installing the bit of the present invention, these devices become extremely effective operation rates due to the improvement of workability (efficiency), and the improvement of the environment of working workers can respond quickly to the aging of experienced workers and greatly secure the safety of construction. It is clear that it will contribute.

[Brief description of the drawings]

FIG. 1 is a plan view of the tip of the bit of the present invention.

FIG. 2 is a partial sectional view of the tip of the bit of the present invention.

FIG. 3 is a plan view of the entire bit of the present invention.

FIG. 4 is a partial sectional view of the entire bit of the present invention;

[Explanation of symbols]

 1 Bit base 2 Hard tip 3 Slit 4 Silver wax bonding surface 5 Intermediate rod connection tip

Claims (2)

[Claims] 1. A drilling bit for a drifter drill, wherein drilling performance is remarkably improved by embedding a cutting tip in a drill bit base having a slit structure at a tip portion and fixing the cutting tip in the slit with silver wax. . 2. A blow hole for discharging dust in the base metal part is provided at a central portion, and the diameter of the passage is adjusted to a flushing hole (blow-off) for a power transmission intermediate rod (hereinafter referred to as a rod) connected to a bit. The total length of the blowhole from the connection tip connected to the hole to the bit tip discharge section is defined as the three stages of the rear expanding part (hereinafter referred to as the rear part), the intermediate standard part (hereinafter the intermediate part), and the tip part. The diameter of the rear part is 1.3 to 2 times the diameter of the flushing hole, and its length is the length obtained by subtracting the length of the middle part and the tip part from the entire length of the blow hole, and the diameter of the middle part is The flushing hole diameter is 0.8-0.
Nine times, the length is 0.5 to 0.8 times, and the diameter of the tip is 1.3 to 2 times the diameter of the flushing hole.
A drill bit for a drifter drill with significantly improved blow clogging, characterized in that the blow clog is doubled (but not more than 1/3 of the bit gauge) and the length is 0.8 to 1.2 times the flushing hole.