JPH0135772Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention relates to a step-type drilling tool that can perform highly accurate drilling.

[Conventional technology]

Generally speaking, among various drilling tools such as gun drills and twist drills, when drilling holes that require particularly high accuracy, multiple steps of different outer diameters are used from the tip of the tool body to the base. A step-type drilling tool with a cutting edge is used.

By the way, in this type of drilling tool, in addition to improving its chip evacuation performance, the cutting edge of the cutting edge at the leading edge plays a guiding role during drilling, which greatly affects the accuracy of hole processing. Improving performance is considered important. For this reason, in conventional drilling tools of this type,
A flow path for guiding cutting oil along the longitudinal direction is formed inside the tool body, and an internal oil supply hole communicating with the flow path is bored in the flank of the cutting blade at the tip of the tool body. Cutting oil is supplied from the hole to the area around the cutting edge at the leading edge. The cutting oil from this internal oil supply hole improves the chip evacuation performance of the cutting edge at the cutting edge mentioned above, and the oil pressure discharges the chips to the outside via the chip evacuation groove. .

[Problem that the invention attempts to solve]

However, in the above-mentioned conventional step-type drilling tool, no internal oil supply hole is provided except on the flank of the cutting edge at the cutting edge, so the outer diameter of the second stage cutting edge is When the outer diameter of the cutting edge is more than twice the outer diameter, or when there are many stages of cutting edges with different outer diameters, cutting oil from the internal oil supply hole at the tip of the cutting edge in the latter stage of the cutting edge may be There was a problem in that the hydraulic pressure of the cutting blade decreased, and chips generated by the cutting blades of all the cutting blade parts could not be smoothly discharged. Moreover, if only the supply pressure of the cutting oil is increased in order to improve the evacuation of chips, the oil pressure of the cutting oil at the tip of the hole will become too high, and conversely, the cutting edge at the tip of the hole will be cut. There was a risk that performance would deteriorate.

[Purpose of invention]

This idea was made in view of the above circumstances,
Even when there are a large number of stepped cutting edges, excellent cutting performance and chip evacuation performance can be obtained.
Therefore, it is an object of the present invention to provide a step-type drilling tool that can perform drilling with high accuracy.

[Means for solving problems]

The drilling tool of this invention has an internal oil supply hole provided in the flank of each of the cutting blades of multiple stages of cutting blade portions having different outer diameters formed from the distal end to the proximal end.

[Effect]

In the case of the drilling tool with the above configuration, by supplying cutting oil from the internal oil supply hole on the flank of the cutting edge of each cutting edge, sufficient hydraulic pressure can be obtained even in the subsequent cutting edge, so that chips can be removed. can be smoothly discharged, and at the same time, the cutting performance of the cutting edge in each cutting edge portion can also be improved.

〔Example〕

FIGS. 1 and 2 show an example of the drilling tool of this invention, which is applied to a step-type two-flute gun drill.

1 and 2, this gun drill (drilling tool) 1 has multiple stages (two stages in the figure) whose outer diameter gradually increases from the distal end to the proximal end of the tool body 2. ) are formed in sequence. Further, chip evacuation grooves 5, 5 each having a V-shaped cross section are formed from the distal end to the proximal end of the tool main body 2 at positions symmetrical to the rotation center on the outer periphery of the tool main body 2. has been done. Cutting edges 6, 6, 7, and 7 extending from the center of rotation to the outer periphery are formed at the edge portions of the surfaces of the cutting edges 3 and 4 facing the rotation direction, respectively. and again,
Flank surfaces 8 and 9 of the cutting edges 6 and 7 are formed on the end faces of the cutting edges 3 and 4 on the tip side of the tool body 2, respectively.

On the other hand, a flow path (not shown) for guiding cutting oil along the rotation center is bored inside the tool body 2. The flanks 8, 9 of the cutting blades 6, 7 are provided with internal oil supply holes 10, 11, which communicate with the flow paths, respectively.

Therefore, in the case of such a gun drill (drilling tool) 1, internal oil supply holes 10, 11 for supplying cutting oil are provided in the flanks 8, 9 of the cutting edges 6, 7 of the respective cutting edges 3, 4. , sufficient hydraulic pressure of cutting oil can be obtained in each of these cutting edge portions 3 and 4. Therefore, chips generated by the respective cutting blades 6 and 7 can be smoothly discharged. In addition, the cutting resistance at each cutting edge 6, 7 is reduced, thereby improving the cutting performance, so it is possible to improve the machining accuracy of hole dimensions and finished surfaces, and furthermore, the cutting resistance at each cutting edge 6, 7 can be improved. It is also possible to obtain effects such as extending the life of the tool 7 and reducing the power required for cutting.

In addition, in the above embodiment, an example in which the drill is applied to a two-blade gun drill 1 is shown, but the invention is not limited to this, and a single-blade gun drill may be used, and other step-type drilling methods such as a twist drill may also be used. It can also be applied to tools.

[Effect of idea]

As explained above, the drilling tool of this invention is
An internal oil supply hole is provided on the flank of the cutting edge of the cutting edge section, which has multiple stages of different outer diameters formed from the distal end to the proximal end. It also provides excellent cutting performance and chip evacuation performance, making it possible to perform highly accurate drilling, as well as extending the life of the cutting edge and reducing the power required for cutting. Obtainable.

[Brief explanation of the drawing]

1 and 2 show an embodiment of the drilling tool of this invention, with FIG. 1 being a side view of the tip, and FIG. 2 being a perspective view of the tip. 1... Gun drill (drilling tool), 2... Tool body, 3, 4... Cutting blade section, 5... Chip discharge groove,
6, 7... Cutting edge, 8, 9... Flank surface, 10, 11
...Internal cutting hole.

Claims (1)

[Scope of utility model registration request] In a step-type drilling tool in which a plurality of cutting edges with different outer diameters are formed from the tip end to the base end, an internal oil supply hole is provided in the flank of the cutting edge of each of the cutting edges. A drilling tool characterized by: