JPH0445767Y2 - - Google Patents

Description

[Detailed description of the invention] (Industrial field of application) The present invention relates to a drill made of cemented carbide used for drilling work, and particularly to a chamfering and dual-purpose drill suitable for use in combination with a chamfering tool. It is something.

(Conventional technology and its problems) When drilling a counterbore hole in a workpiece, there is a method of counterboring the periphery of the hole cut with a general-purpose drill using a separate chamfering tool, or drilling and counterbore simultaneously. However, the former method has extremely poor work efficiency, and the latter method requires expensive specialized tools, so it is difficult to process various sizes. It has the disadvantage that it is difficult to utilize when it must be done.

In order to solve this problem, as shown in Fig. 1, a chamfering tool 4 is set in a tool holder 2 via an attachment 3 to which a general-purpose drill 1 is attached, and the drill 1 and the chamfering tool 4 are connected together.
It has been considered that the chamfering bit 4 can continuously perform the chamfering operation when the drilling operation reaches a certain depth by rotating the drill bit 1 as a unit, but in the past, the general-purpose drill 1 was Since the tip of the chamfering tool 4 was in use, the tip of the chamfering tool 4 should be brought into contact with the land circumferential surface 5 of the drill 1, or the tip of the chamfering tool 4 should be brought into contact with the cutting waste feeding groove 6 of the drill 1 as shown in FIGS. 1 and 2. The chamfering tool 4 had to be set in the tool holder 2 with the tip of the chamfering tool 4 loosely fitted inside the tool holder.

In the figure, 7 is a bolt for fixing the drill, 8 is a bolt for fixing the attachment 3 to the tool holder 2 with the fixing position adjusted in the axial direction, and 9 is a bolt for attaching the chamfering tool 4 to the tip of the attachment 3 at a predetermined angle. Further, a bolt is fixed with the position adjusted in the distance direction with respect to the drill 1, 10 is a workpiece, 11 is a hole drilled with the drill 1, and 12 is a chamfered portion machined with the chamfering tool 4.

When the tip of the chamfering tool 4 is brought into contact with the land circumferential surface 5 of the drill 1 as in the former case, a gap is created between the tip of the chamfering tool 4 and the land circumferential surface 5 of the drill 1. This increases the possibility that burrs will remain at the boundary between the hole 11 and the chamfered portion 12, making it difficult to obtain a high-quality counterbore hole.
In addition, when the tip of the chamfering tool 4 is loosely fitted inside the cutting waste sending groove 6 of the drill 1 as in the latter case, the cutting waste coiled inside the groove 6 and sent out is If it gets entangled with the chamfering tool 4 and gets stuck in the groove 6, the cutting operation itself has to be interrupted, or the hole 1
There is also a possibility that the inner surface of 1 may be damaged.

In order to solve the problems of this conventional technology, Jikosho
As shown in Publication No. 49-36548, the cutting edge of the cutting tool is positioned in the groove formed after the second corner of the drill cutting edge to prevent clogging of the aforementioned cutting waste delivery groove with cutting waste. Although such a technique has been proposed, even this conventional technique has the disadvantage that chamfering cannot be performed with sufficient accuracy.

That is, when chamfering cutting is performed using a cutting tool, cutting resistance is naturally applied to the cutting tool. This cutting tool is attached in a cantilevered manner to an arm that extends long from the tool holder to perform cutting work.
The above-mentioned cutting resistance applied to the cutting tool causes a horizontal vibration phenomenon in the cutting tool, which makes it impossible to perform chamfering accurately. There was a problem that the parts were broken. In this case, the arm that holds the cutting tool can be made thicker to increase its rigidity, but since the arm must be attached so that it does not protrude too much into the tool holder, there is a limit to how thick the arm can be. However, there is a problem in that the rigidity of the arm cannot be sufficiently increased.

The present invention aims to solve these problems all at once and to minimize the horizontal shaking phenomenon of the cutting tool even if the arm that holds the cutting tool cannot have sufficient rigidity.

(Means for Solving the Problems) The present invention proposes a dual-use chamfering drill that can solve the conventional problems that occurred when used in combination with a chamfering tool as described above. The feature is that a drill 13 and an attachment 3 are attached to the tool holder 2 in parallel to the drill 13, and a chamfering bit 4 is attached to the tip of the attachment 3 in an inclined manner toward the drill 13, while the drill cutting edge 14 Peripheral surface 17 of the land portion adjacent to the cutting waste sending groove 15 formed on the rotation direction side
, an auxiliary groove 16 for loosely fitting a chamfering tool with a substantially concave cross section.
is formed along the cutting waste delivery groove 15 up to the shank side terminal end of the delivery groove 15, and the tip of the chamfering tool 4 is loosely fitted into the chamfering tool auxiliary groove 16 for loose fitting. It is at the point where it becomes.

(Example) An example of the present invention will be described below based on FIGS. 3 and 4.

Reference numeral 13 denotes a chamfering and chamfering drill of the present invention consisting of a drill body 13a and a shank portion 13b, in which a groove 15 for sending out cutting waste is formed in the drill body so that one end is adjacent to the drill cutting edge 14 at the tip in the direction of rotation. It is formed in a spiral shape on the circumferential surface of 13a. 1
6 is an auxiliary groove according to the present invention, and the groove 1 is formed on the peripheral surface 17 of the land portion between the grooves 15 for sending out cutting waste.
5 and up to the end of the groove 15 on the shank portion 13b side, the auxiliary groove 16 has a substantially concave cross-sectional shape, and the inner peripheral surface of the concave auxiliary groove 16 a pair of support surfaces 16 on
a, 16b are formed. Reference numeral 18 denotes an oil hole that is drilled in the axial direction as necessary.

In the illustrated embodiment, the tip of the auxiliary groove 16 is opened in the drill tip surface 19, but the length can also be extended to the front of the drill tip surface 19, but the rear end of the auxiliary groove 16 is opened in the drill tip surface 19. The cutting edge 14 is formed to have a length up to the end of the cutting waste feeding groove 15 in which the cutting edge 14 is formed.

The drill 13 of the present invention configured as described above is
Just like a conventional general-purpose drill, it can be set in a tool holder 2 in place of the drill 1 shown in FIG. 1 and used for drilling work. When used together with the chamfering tool 4 as shown in Fig. 1,
The chamfering tool 4 may be attached to the tool holder 2 via the attachment 3 so that the tip of the chamfering tool 4 fits loosely into the auxiliary groove 16 as shown by the imaginary line in FIG.

In this way, when drilling is performed while using the chamfering tool 4 in combination, when the drilling with the drill 13 reaches a predetermined depth, the chamfering using the chamfering tool 4 is continuously performed, It is possible to machine counterbore holes all at once,
Cutting debris generated by the cutting action of the cutting blade 14 is mainly sent out of the machined hole through the cutting debris sending groove 16, and is sent out to the outside of the machined hole.
There is no or very little possibility that the tip of the auxiliary groove 16 will be fed out through the auxiliary groove 16 into which it is loosely fitted.

Furthermore, since the chamfering operation using the chamfering tool is performed at the final stage of the drilling operation using the drill, the chamfering tool must be installed near the end of the shank portion of the drill cutting edge. In this regard, according to the present invention, the auxiliary groove 1 for loosely fitting the chamfering tool
6 is formed to have the same length up to the end on the shank portion 13b side of the cutting waste feeding groove 15 formed adjacent to the drill cutting edge 14, so even when the drilling length by the drill is at its maximum, this drilling operation is easy. The chamfering tool 4 can be attached at a position that does not interfere with the operation.

Furthermore, as mentioned above, since the chamfering tool 4 is held in a cantilevered state at the tip of the attachment 3, a large cutting resistance is applied to the tool 4 during the chamfering operation using the tool 4. A horizontal shaking phenomenon is about to occur in the cutting tool 4, but the chamfering cutting tool loose fitting auxiliary groove 16 in which the cutting tool 4 is located is formed with a concave cross section, and the supporting surfaces 16a and 16b face each other on both sides of the tip of the cutting tool 4. Therefore, when the cutting tool 4 shifts slightly in the lateral direction during cutting, the side surface of the tip of the cutting tool 4 touches the support surface 16a.
or 16b, and prevents further lateral deviation, so that during cutting, the base end of the cutting tool 4 is supported by the attachment 3, and the tip end is supported by the support surface 16a. or 16
b, it is possible to minimize the occurrence of the horizontal shaking phenomenon, and to perform chamfer cutting work accurately, and also to prevent the cutting tool 4 from breaking due to excessive cutting resistance applied to the cutting tool 4. do not have.

(Operations and Effects of the Invention) As described above, according to the drill of the present invention, the land located at a position away from the cutting waste sending groove through which the cutting waste generated by the cutting action of the cutting blade passes during cutting operation. Since an auxiliary groove is formed on the circumferential surface of the part, there is no or very little possibility that cutting chips will pass through the auxiliary groove. To smoothly discharge the cutting tool without clogging the groove at the tip of the cutting tool in the same way as when a chamfering tool is not used together.

Therefore, there is no fear of interruption of work or damage to the inner circumferential surface of the machined hole due to clogging with cutting chips, and it is possible to perform the work smoothly and obtain a high-quality machined hole. Moreover, since the tip of the chamfering tool can be used with the tip of the drill penetrating inside the drill, there is no risk of leaving burrs at the boundary between the hole and the chamfer, making it possible to obtain a high-quality counterbore hole. .

Furthermore, according to the present invention, the auxiliary groove for loosely fitting the chamfering tool is formed all the way to the end on the shank side of the cutting chip delivery groove formed adjacent to the drill cutting edge, so that when the drilling length by the drill is maximum, Even in this case, the chamfering tool can be installed at a position that does not interfere with the drilling operation, and the chamfering operation can be carried out smoothly.

In particular, according to the present invention, the auxiliary groove for loosely fitting the chamfering tool in which the tool is located is formed with a concave cross section,
Since the concave inner surface faces both sides of the tip of the tool,
When the cutting tool shifts slightly laterally during cutting, the side surface of the tip of the cutting tool is supported by the concave inner surface.
Further lateral deviation is prevented, and as a result, during cutting, the proximal end of the cutting tool is supported by the cutting tool holding member, and the distal end thereof is supported by the concave inner surface, causing the cutting tool to sway horizontally. The occurrence of such phenomena can be kept to a minimum, chamfering cutting work can be performed accurately, and the cutting tool will not break even if an excessive cutting resistance is applied to the tooling tool.

[Brief explanation of the drawing]

Figure 1 is a side view showing how a conventional general-purpose drill is used, Figure 2 is a front view of the drill showing the positional relationship between the drill and the chamfering tool, and Figure 3 is the position of the drill of the present invention and the chamfering tool. FIG. 4 is a front view of the drill showing the relationship, and FIG. 4 is a perspective view of the drill of the present invention. DESCRIPTION OF SYMBOLS 1... Conventional general-purpose drill, 2... Tool holder, 3... Attachment, 3a... Drill body, 3b... Shank part, 4... Chamfering tool bit, 5, 17... Land part circumferential surface, 6, 15... Groove for sending out cutting waste, 11... Machined hole, 12
... Chamfered portion, 13 ... Drill of the present invention, 14 ...
Drill cutting blade, 16...Auxiliary groove for loose fitting of chamfering tool.

Claims (1)

[Scope of utility model registration request] A drill and an attachment are attached to the tool holder in parallel with the drill, and a chamfering tool is attached to the tip of the attachment in an inclined manner toward the drill, while a groove for sending out cutting chips is formed on the rotational direction side of the drill cutting edge. An auxiliary groove for loosely fitting a chamfering tool with a substantially concave cross section is formed on the peripheral surface of the land adjacent to the chamfering tool along the cutting waste delivery groove up to the shank-side terminal end of the delivery groove. A drill for chamfering and chamfering, the tip of which is loosely fitted into the auxiliary groove for loosely fitting the chamfering bit.