JP2000061932A - Core bit with water flow valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable a cooling water to be efficiently supplied to a cutting point all through the process from the start of using and the end of using a core bit regardless of the wear and the height of a cutting blade part by mounting shut-off members for controlling the cooling water which are attachable to and detachable from opening parts formed in the cutting blade part or are breakable. SOLUTION: The core bit 10 is structured of 7 diamond segments 16 fitted fixedly to the tip part of a cylindrical metal base 12 as a cutting blade part 15, and rubber shielding members 18, 20 are provided at two spots of space formed between the segments 16 respectively. When the area of a water passage to be formed by opening parts formed in the cutting blade part 15, is too wide, the leakage of a cooling water from the spaces is prevented from occurring by the shielding members 18, 20 which shield the opening parts. In addition, when the cutting blade part 15 is worn out, the shielding members 18, 20 are cut or removed in accordance with the wear condition. Thus it is possible to secure the appropriate area of the water passage and therefore, secure a stable cutting sharpness all the time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core bit used for drilling hard members such as concrete structures, asphalt, stone materials, and refractory tiles.

[0002]

2. Description of the Related Art At the tip of a core bit, there is formed a cutting edge portion made of an abrasive material layer using diamond abrasive grains for perforating asphalt, concrete or rock.

The type of the cutting edge portion differs depending on the processing purpose, and is a surface set type in which a small-diameter diamond is further mounted on the surface using a matrix.
Known are an impregnated type in which diamond abrasive grains and a metal binder are mixed and sintered by a powder metallurgy method, and an electrodeposition type in which diamond abrasive grains are fixed by an electrodeposition method using a metal such as nickel.

When drilling a work material such as concrete using such a core bit, cooling water is used to discharge chips generated during work and to cool a cutting point.

FIG. 6 is a perspective view showing a conventional core bit.
Reference numeral 51 is a cylindrical base metal, 53 is a diamond segment fixed to the tip of the base metal 51 with a gap, 55 is a gap formed between the segments, and 57 is a cooling water passage hole, not shown. Each swivel connected to the machine is shown.

Chips generated mainly near the tips of the segments 53 due to the punching work are discharged by the cooling water supplied from the swivel 57 to the outside as shown by the arrows through the outer peripheral side of the base metal 51. Such cooling water moves as a water passage through the gap 55 formed between the segments 53.

The gap 55 as a passage for the cooling water occupies a considerable space at the beginning of use, and the flow of the cooling water is smooth, but when the segment 53 is worn out due to use, the passage area is gradually narrowed. As a result, the flow of cooling water becomes poor, resulting in a decrease in the chip discharge efficiency and, in turn, a decrease in the drilling capacity.

In order to solve such a problem, the inventors of the present invention have provided a diamond having a slit portion which can be used as a water passage for cooling water by removing the filler when the segment 53 is worn. The core drill first, the actual flat 4
-26706.

[0009]

On the other hand, as described above, the cooling water flows through the gap 55 between the segments 53 as a main water passage, but the cooling water is most needed.
A contact point between the segment 53 and a work material such as concrete is a so-called cutting point, and when the space formed by the gap 55 between the segments 53 is too large, such as when the segment 53 is new or when the segment 53 is high, on the contrary, However, the cooling water may move only from this portion, and it may be difficult to supply the cooling water sufficiently to the cutting point.

The problem to be solved by the present invention is to provide an effective means for efficiently supplying cooling water to the cutting point from the beginning to the end of use regardless of the wear of the cutting edge portion or its height. Especially.

[0011]

In order to solve the above problems, the present invention provides a core bit in which a cutting edge portion made of an abrasive layer is formed at the tip of a cylindrical base metal, and at least one portion is provided in the cutting edge portion. The above-mentioned opening is provided, and a detachable or breakable shielding member for cooling water control is attached to the opening.

Here, "detachable or breakable" includes all that can be removed by removing, or cutting by scissors, pulling out with pliers, etc., and removable by the will of the operator. .

The material of the shielding member is not particularly limited as long as it is "detachable or rupturable" such as rubber, resin or metal, but rubber or resin is preferable from the viewpoint of ease of processing and cost.

By providing such a shielding member,
When the area of the water passage formed by the opening provided in the cutting edge is too wide, the shielding member that blocks the opening prevents the cooling water from leaking from this space, and the cutting edge is worn. At this time, it is possible to secure an appropriate water passage area by cutting or removing the shielding member according to the wear condition.

Here, it is desirable that the thickness of the shielding member is thinner than the thickness of the cutting edge portion, that is, the outer surface of the shielding member is inside the outer surface of the cutting edge portion. By making the thickness of the shielding member thinner than the thickness of the cutting edge portion, the frictional resistance is suppressed and the sharpness is improved.

Furthermore, in addition to the above-mentioned constitution, the actual flat opening 4-267
As disclosed in Japanese Patent Laid-Open No. 06-06, it is desirable that a portion of the base metal to which the shielding member is attached has a through hole for cooling water flow that is blocked by the shielding member. With such a structure, the cooling water can be supplied to the cutting point until the cutting edge portion is almost worn, and it is possible to maintain a stable sharpness until the end.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION The features of the present invention will be described below in detail with reference to the embodiments shown in the drawings. 1 is a perspective view of a core bit showing an embodiment of the present invention, and FIG. 2 is a partial vertical sectional view of the core bit shown in FIG.

The core bit 10 of this embodiment has seven diamond segments 16 at the tip of a cylindrical base metal 12.
Are fixed to form the cutting edge portion 15, and rubber-made shielding members 18 and 20 are provided in two spaces formed between the segments 16.

The shielding member 18 is provided so as to completely close the gap between the adjacent segments 16, and the shielding member 20 is provided so that there is a gap between the adjacent segments 16.

As shown in a partially enlarged view of FIG. 1, the shielding member 20 is composed of a main body portion 20a forming a part of an arc and a semicircular protrusion portion 20b protruding downward from the center thereof.
b is attached so as to close the semicircular through hole 12a formed in the base metal 12. In addition, the shielding members 18, 20
As shown in the cross-sectional view of FIG. 2, the thickness is smaller than that of the segment 16 by about 1.0 mm, which suppresses the frictional resistance.

Both the shielding members 18 and 20 are firmly fixed to the base metal 12 with an adhesive and do not come off due to the punching work, but because they are made of rubber, they can be cut with scissors, and with pliers or the like. It can also be removed.

Next, referring to FIG. 3 showing the state of change of the shielding member due to wear of the segments and FIG. 4 showing the flow of cooling water in each state, the core bit 1 is referred to.
A method of using 0 will be described. Here, FIG. 3 (a) shows a state where the core bit 10 is first used, FIG. 3 (b) shows a state of being used, and FIG. 3 (c) shows a state of being almost used, and FIGS. ) And (c) are shown in FIG.
Flows of the cooling water corresponding to the states shown in (b) and (c) are respectively shown.

As shown in FIGS. 3 (a) and 4 (a),
At the stage when the height of the segment 16 is high at the beginning of using the core bit 10, the cooling water passage area formed between the segments 16 is considerably large, and at this stage, the shielding members 18, 20 partially cover this space. Even if it blocks the cooling water, the cooling water is efficiently supplied to the cutting point.

This state is the same in the middle stage of use of the core bit 10 as shown in FIGS. 3 (b) and 4 (b), but the flow of the cooling water becomes worse due to the wear of the segment 16. In this case, the water passing area can be secured by partially cutting the shielding members 18 and 20 as shown by the broken line in FIG.

Further, as shown in FIGS. 3C and 4C, when the core bit 10 reaches the end of use,
Since the water passage area of the cooling water formed between the segments 16 is considerably narrowed and it becomes impossible to secure a predetermined water passage area,
The shielding members 18 and 20 are completely removed. by this,
Not only can the water passage area be secured, but the through hole 12a that is blocked by the protrusion 20b of the shielding member 20 will also function as a water passage.

As described above, according to the core bit 10 of the present embodiment, it becomes possible to efficiently supply the cooling water to the necessary places from the beginning of use of the core bit 10 to the end of use thereof, thereby maintaining a stable sharpness. It becomes possible.

FIG. 5 is a partial perspective view of a core bit according to another embodiment of the present invention, showing an example of application to a core bit whose cutting edge portion is a rim type.

In the core bit 11 of this embodiment, a rim type cutting edge portion 15 made of a diamond abrasive layer is formed at the tip of a cylindrical base metal 13. This cutting edge 15
The shielding member 21 with the protrusion 21b is attached to the opening provided at one location. The shield member 21 is similar to the shield member 20 shown in FIG.

Also in the core bit 11 of this embodiment,
The shield member 21 performs the same function as the shield member 20 in the core bit 10 shown in FIG. 1, and can efficiently supply the cooling water to a necessary place from the beginning of use of the core bit 11 to the end of use thereof, which is stable. The sharpness can be maintained.

[Test Example] Core bit 10 shown in FIG.
The (invention product) and the conventional product without the shielding member were subjected to a concrete perforation test under the following conditions. In the case of the invention product, when the shielding member was cut once (Example 1) and cut twice (Example 2) during the use stage.
A perforation test was performed on the. Table 1 shows the test results.

[0031]   Test condition     Core bit: Outer diameter 110 mm                 Segment size L25 × W2.8 × X7.0mm, 9 pieces                 Gap between segments 18 parts in Figure 1 9.5mm                                   20 part of FIG. 1 44.0 mm                                   Comparative product 13.4 mm     Machine: Electric motor 100V, 10.5A, rotation speed 1000rpm     Drilling method: Wet (cooling water amount 1.5 liters / min)                 Perforation depth of 400 mm per operation, manual feed     Work Material: Reinforced Concrete

[0032]

[Table 1]

As can be seen from Table 1, in the case of Example 1, sharpness was restored by cutting the shielding member once in the middle of the use stage, and the punching speed was improved by about 17% as compared with the conventional product. There is. In the case of Example 2, the shield member was cut twice in the middle of the use stage, so that the drilling speed was further improved, which was about 23% higher than that of the conventional product. In addition, since the cooling water is effectively supplied to the cutting point, the wear of the segment is also reduced. Compared with the conventional product, the life of the first embodiment is about 20%, and the life of the second embodiment is about 45%. It is increasing.

[0034]

According to the present invention, the following effects can be obtained.

(1) At least one opening is provided in the cutting edge, and a removable or breakable shielding member for cooling water control is attached to the opening to provide the opening provided in the cutting edge. If the area of the water passage formed by the section is too wide, the shielding member that blocks the opening prevents the leakage of cooling water from this space, and when the cutting edge section becomes worn, wear it. By cutting or removing the shielding member depending on the situation, it is possible to secure an appropriate water passage area.

(2) By making the thickness of the shielding member thinner than the thickness of the cutting edge portion, the friction resistance is suppressed and the sharpness is improved.

(3) It is desirable that a portion of the base metal to which the shielding member is attached has a through hole for cooling water flow, which is closed by the shielding member. With such a structure, the cooling water can be supplied to the cutting point until the cutting edge portion is almost worn, and stable cutting performance can be maintained until the end.

[Brief description of drawings]

FIG. 1 is a perspective view showing a core bit according to an embodiment of the present invention.

FIG. 2 is a vertical cross-sectional view of the core bit shown in FIG.

FIG. 3 is a perspective view showing a state of change of a shielding member due to wear of a diamond segment of the core bit shown in FIG.

FIG. 4 is an explanatory diagram showing a flow of cooling water in the core bit shown in FIG. 1.

FIG. 5 is a partial perspective view showing a core bit of another embodiment.

FIG. 6 is a perspective view of a conventional core bit.

[Explanation of symbols]

10, 11 core bits 12,13 money 12a through hole 14 swivel 15 cutting edge 16 diamond segments 18, 20, 21 Shielding member 20a main body 20b, 21b protrusion

Claims (4)

[Claims] 1. A core bit in which a cutting edge portion made of an abrasive layer is formed on a tip portion of a cylindrical base metal, at least one opening portion is provided in the cutting edge portion, and the opening portion is detachable or rupturable. A core bit equipped with a shielding member for possible cooling water control. 2. The core bit according to claim 1, wherein the shielding member is made of rubber, resin, or metal. 3. The core bit according to claim 1, wherein the shielding member is a member thinner than the cutting edge portion. 4. The core bit according to claim 1, wherein a through hole for cooling water passage closed by the shielding member is formed in a portion of the base metal to which the shielding member is attached.