JPH11129108A - Through-hole drilling method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a deep through-hole drilling method, capable of reducing labor for arrangement and shortening a time for drilling. SOLUTION: Two gun drills 2a, 2b are opposed to each other at both sides of a work 1 to drill two holes 3a, 3b at both sides of the work 1 at the same time. In drilling procedures that the right gun drill 2a is moved back in the condition fitted-in the work 1 and the left gun drill 2b is used to perforate two holes 3a, 3b before the holes 3a, 3b are perforated at both sides, the reversion of the work and the demounting of the drill or an oil tap are eliminated and a drilling time is shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a deep through hole in a work.

[0002]

2. Description of the Related Art When drilling a deep through-hole in a work, if the through-hole is longer than the drill length or if the diameter of the through-hole is different from the middle, first, drilling from one end of the work to the middle. After that, the work is turned over, and a hole is formed from the other end to penetrate the holes from both sides.

[0003] In the drilling of the deep through-hole, a type of drill that supplies high-pressure cutting oil and discharges chips backward is used. Drills of this type include gun drills and drills with oil holes used for drilling relatively small diameters, and BTAs used for drilling large diameters.
(Boring and Trepaning Association) There is a tool.

A gun drill and a drill with an oil hole supply high-pressure cutting oil from the inside of a shank, inject the cutting oil from an oil hole at the tip of the drill, and chip along a V-groove or a spiral groove provided on the outer periphery of the shank. And the cutting oil is discharged backward. B
Conversely, the TA tool supplies high-pressure cutting oil from the outer peripheral side of the shank, and discharges chips and cutting oil from the oil hole at the tip of the tool through the inside of the shank. When using a gun drill and a BTA tool for drilling, the tool side is normally driven to rotate, and when using a drill with oil holes, the work side is driven to rotate.

[0005] Fig. 2 shows a conventional processing procedure when a through hole having a different diameter is formed in the rod-shaped workpiece 1 on the way using a gun drill. First, as a first step, as shown in FIG. 2A, a first gun drill 9a is arranged at one end side of the work 1 and a hole 10 having a required diameter is reached near the center of the work 1.
a is processed. Thereafter, the gun drill 9a is retracted and extracted from the work 1.

The gun drill 9a is formed by a shank 11 and a tip 12 at the tip.
A V-groove 13 extending in the axial direction is provided on the outer peripheral surface of the. An oil hole 14 having a crescent cross section for supplying high-pressure cutting oil is provided inside the shank 11, and an oil hole 15 connected to the oil hole 14 and opening at the tip is provided inside the tip 12. During cutting, high-pressure cutting oil is injected from the oil hole 15. This injected cutting oil is discharged to the outside through the V-groove 13 together with the chips.

In the second step, as shown in FIG. 2 (b), the work 1 is turned left and right, an oil plug 17 with a packing 16 is inserted into the processed hole 10a, and the first The gun drill 9a is replaced with a second gun drill 9b having a different diameter, and a hole 10b having a required diameter is machined from the end face of the work 1 opposite to the hole 10a. This drilling is performed until the hole 10b penetrates the hole 10a, and then the second gun drill 9b and the oil stopper 17 are formed.
Is extracted from the work 1 to complete the machining process.

The above-described drilling process using a gun drill is basically the same when using a drill with an oil hole or a BTA tool.

[0009]

The above-mentioned conventional drilling method involves reversing the work and attaching and detaching the drill and the oil plug, so that a great deal of labor is required for the setup, and the time required for the machining process is increased. Also has the problem of becoming longer.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method of drilling a deep through-hole, which requires less time and effort for setup and can reduce the time required for the processing step.

[0011]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention uses a drill for supplying high-pressure cutting oil and discharging chips backward, and drills a through hole in a work. In performing the above, two types of drills are arranged coaxially on both sides of the work so as to face each other, the two drills are advanced to start drilling from both sides of the work, and before the two drills hit. Then, a method is adopted in which the advance of one of the drills is stopped, this drill is retracted to a position where it cannot be completely removed from the work, and only the other drill is advanced to penetrate the holes from both sides of the work.

That is, two drills of the above-described type are arranged on both sides of the work so as to face each other, and drilling is performed simultaneously from both sides of the work. Therefore, the processing time can be reduced, and the work can be turned over and the drill can be replaced. It becomes unnecessary, and before the two holes penetrate, one of the drills is retracted to the position where it fits in the work and used as a substitute for the oil plug. Can be.

[0013] Further, by making the cutting oil supply pressure of the drill to be retreated halfway higher than the cutting oil supply pressure of the other drill, chips generated in the cutting process for penetrating the two holes are reduced. It can be smoothly discharged to the rear of the other drill.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 (a) and 1 (b). In this embodiment, similarly to FIG. 2, a through hole having a different diameter is formed in the rod-shaped workpiece 1 in the middle. As shown in FIG.
Two gun drills 2 with different diameters on the left and right sides of the work 1
a and 2b are coaxially arranged facing each other, and two holes 3a and 3b are machined by the respective gun drills 2a and 2b from the left and right sides of the work 1 to the vicinity of the center.

The gun drills 2a, 2b are respectively formed by shank 4a, 4b and tip 5a, 5b at the tip.
V-grooves 6a, 6b are provided on the outer peripheral surface of each of the shank 4a, 4b and the tip 5a, 5b so as to be continuous in the axial direction. Inside each shank 4a, 4b, there are provided lubrication holes 7a, 7b having a crescent-shaped cross section for supplying high-pressure cutting oil, and inside each tip 5a, 5b, they are connected to the lubrication holes 7a, 7b, respectively. Oil holes 8a and 8b are provided.

High-pressure cutting oil is injected from each of the oil holes 8a and 8b, and the injected cutting oil is discharged to the outside through the respective V-grooves 6a and 6b together with chips generated in the processing of the holes 3a and 3b. Have been. The right gun drill 2
The pressure of the cutting oil supplied to the oil supply hole 7a is set higher than the pressure of the cutting oil supplied to the oil supply hole 7b of the left gun drill 2b.

After the processing has progressed to the state shown in FIG.
As shown in FIG. 1B, the right gun drill 2a retreats, the left gun drill 2b advances, and the two
a, 3b are penetrated and drilling is completed. As described above, the pressure of the cutting oil supplied to the oil supply hole 7a is:
Since the pressure is set higher than the pressure of the cutting oil supplied to the oil supply hole 7b, the chips generated at this time will
Through the gun drill 2b on the left.

In the above embodiment, the case where a gun drill is used has been described. However, even when a drill with an oil hole or a BTA tool is used, drilling can be performed in exactly the same procedure. However, when the work is rotationally driven using a drill with an oil hole or the like, one of the drills needs to have a reverse screw.

[0019]

As described above, according to the method for boring a through hole of the present invention, two drills of the type for supplying high-pressure cutting oil to both sides of a work and discharging chips backward are arranged. , Drill holes from both sides of the work at the same time,
Before drilling holes from both sides, one of the drills was retracted while fitted into the work, and the other drill was used to penetrate the holes from both sides. The work of attaching and removing the plug can be made unnecessary, and the processing time can be shortened.

[Brief description of the drawings]

1A and 1B are explanatory views of a drilling procedure according to an embodiment.

2A and 2B are explanatory views of a conventional drilling procedure.

[Explanation of symbols]

 1 Work 2a, 2b Gun drill 3a, 3b Hole 4a, 4b Shank 5a, 5b Tip 6a, 6b V groove 7a, 7b Oil supply hole 8a, 8b Oil hole 9a, 9b Gun drill 10a, 10b Hole 11 Shank 12 Tip 13 V groove 14 Oil supply Hole 15 oil hole 16 packing 17 oil stopper

Claims (2)

[Claims] When drilling a through hole in a work using a drill that supplies high-pressure cutting oil and discharges chips backward, two drills of the above type are opposed to each other on both sides of the work. And placed on the same axis,
One drill is advanced to start drilling from both sides of the work, and before the two drills hit, one drill is stopped, and this drill is retracted to a position where it cannot be removed from the work, and the other drill Only move forward,
A method for drilling a through hole, wherein holes from both sides of the work are made to pass through. 2. The method for drilling a through hole according to claim 1, wherein the cutting oil supply pressure of the drill to be retracted halfway is higher than the cutting oil supply pressure of the other drill.