JP3926446B2 - Through hole drilling method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for drilling deep through holes in a workpiece.
[0002]
[Prior art]
When drilling a deep through hole in the workpiece, if the through hole is longer than the drill length or if the diameter of the through hole is different from the middle, first drill from one end of the workpiece to the middle. The workpiece is inverted and drilled from the other end side to penetrate the holes from both sides.
[0003]
In the drilling of the deep through hole, a drill of a type that supplies high-pressure cutting oil and discharges chips backward is used. As this type of drill, there are a gun drill and oil hole drill used for drilling a relatively small diameter, and a BTA (Boring and Trepaning Association) tool used for drilling a large diameter.
[0004]
Gun drills and drills with oil holes supply high-pressure cutting oil from the inside of the shank, spray the cutting oil from the oil hole at the tip of the drill, and cut chips and cutting oil along V grooves and spiral grooves provided on the outer periphery of the shank. Is discharged backwards. In contrast, the BTA 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. In the drilling process, when using a gun drill and a BTA tool, the tool side is normally driven to rotate, and when using a drill with an oil hole, the workpiece 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 middle of a rod work 1 using a gun drill. First, as a first step, as shown in FIG. 2A, the first gun drill 9 a is disposed on one end side of the work 1, and a hole 10 a having a required diameter is machined to the vicinity of the center of the work 1. Thereafter, the gun drill 9a is retracted and extracted from the workpiece 1.
[0006]
The gun drill 9a is formed of a shank 11 and a tip 12 at the tip, and an outer peripheral surface of the shank 11 and the tip 12 is provided with a V groove 13 continuous in the axial direction. An oil hole 14 having a crescent-shaped cross section for supplying high-pressure cutting oil is provided in the shank 11, and an oil hole 15 that is continuous with the oil supply hole 14 and opens at the tip is provided in the chip 12. At the time of cutting, high-pressure cutting oil is injected from the oil hole 15. The injected cutting oil is discharged to the outside through the V groove 13 together with the chips.
[0007]
In the second step, as shown in FIG. 2 (b), the workpiece 1 is reversed left and right, and the oil plug 17 with the packing 16 attached is inserted into the processed hole 10a, and the first gun drill 9a is It replaces | exchanges for the 2nd gun drill 9b from which a diameter differs, and the hole 10b of a required diameter is processed from the end surface on the opposite side to the said hole 10a of the workpiece | work 1. FIG. This drilling process is performed until the hole 10b penetrates the hole 10a, and then the second gun drill 9b and the oil plug 17 are extracted from the workpiece 1 to complete the processing process.
[0008]
The above-described drilling process using the gun drill is basically the same when using a drill with an oil hole or a BTA tool.
[0009]
[Problems to be solved by the invention]
The conventional drilling method described above involves work reversal work, drill and oil plug attachment / detachment work, and therefore requires a lot of labor for setup and increases the processing time.
[0010]
Accordingly, an object of the present invention is to provide a deep through-hole drilling method that can reduce the time required for the machining process with less setup work.
[0011]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, the present invention uses a drill of a type that supplies high-pressure cutting oil and discharges chips to the rear, and when drilling a through-hole in a workpiece, the two on both sides of the workpiece. Two drills of the above type are placed on the same axis facing each other, the two drills are advanced to start drilling from both sides of the workpiece, and one drill is stopped before the two drills hit Thus, a method was adopted in which the drill was retracted to a position where it could not be removed from the workpiece, and only the other drill was advanced to penetrate the holes from both sides of the workpiece.
[0012]
In other words, two drills of the above-mentioned type are arranged facing each other on both sides of the workpiece, and drilling is performed simultaneously from both sides of the workpiece, so that the machining time can be shortened and work reversal or drill replacement becomes unnecessary. In addition, since one of the drills is retracted to the position where it is fitted into the workpiece before the two holes penetrate, and the oil plug is used as a substitute, it is possible to eliminate the need for attaching and removing the oil plug.
[0013]
Further, by making the cutting oil supply pressure of the drill that is retreated in the middle higher than the cutting oil supply pressure of the other drill, chips generated in the cutting process for penetrating the two holes are removed. It can be smoothly discharged to the rear of the drill.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS. 1 (a) and 1 (b). In this embodiment, as in FIG. 2, through-holes having different diameters are formed in the rod work 1 in the middle. As shown in FIG. 1 (a), two gun drills 2a and 2b having different diameters are arranged on the left and right sides of the work 1 so as to face each other and coaxially. Two holes 3a and 3b are machined from both sides to the vicinity of the center.
[0015]
The gun drills 2a and 2b are each formed of shanks 4a and 4b and tips 5a and 5b at the tips, and V-grooves 6a and 6b connected in the axial direction are provided on the outer peripheral surfaces of the shanks 4a and 4b and the tips 5a and 5b. It has been. Each shank 4a, 4b is provided with a crescent-shaped oil supply hole 7a, 7b for supplying high-pressure cutting oil, and each tip 5a, 5b is connected to the oil supply hole 7a, 7b, respectively, Are provided with oil holes 8a and 8b.
[0016]
High-pressure cutting oil is injected from the oil holes 8a and 8b, and the injected cutting oil is discharged to the outside through the V-grooves 6a and 6b together with chips generated in the processing of the holes 3a and 3b. . The pressure of the cutting oil supplied to the oil supply hole 7a of the right gun drill 2a is set higher than the pressure of the cutting oil supplied to the oil supply hole 7b of the left gun drill 2b.
[0017]
After the processing has progressed to the state of FIG. 1A, as shown in FIG. 1B, the right gun drill 2a is retracted and the left gun drill 2b is advanced so that the two holes 3a and 3b are opened. Drilling has been completed. As described above, since 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, chips generated at this time pass through the V groove 6b. And is discharged to the rear of the left gun drill 2b.
[0018]
Although the above embodiment has been described with respect to the case of using a gun drill, drilling can be performed in exactly the same procedure when using a drill with an oil hole or a BTA tool. However, when the workpiece is rotationally driven using a drill with an oil hole or the like, one of the drills needs to have a reverse screw.
[0019]
【The invention's effect】
As described above, in the through hole drilling method according to the present invention, two types of drills that supply high-pressure cutting oil to both sides of a workpiece and discharge chips rearward are arranged opposite to each other, from both sides of the workpiece. Drilling was performed at the same time, and before the holes from both sides penetrated, one drill was retracted while being fitted in the work, and the other drill was made to penetrate the holes from both sides. It is possible to eliminate the reversing work and the work of attaching and detaching the drill and oil plug, and the processing time can be shortened.
[Brief description of the drawings]
1A and 1B are explanatory diagrams of a drilling procedure of the embodiment. FIG. 2A and b are explanatory diagrams of a conventional drilling procedure. DESCRIPTION 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)

When drilling a through-hole in a workpiece using a drill that supplies high-pressure cutting oil and discharges chips backward, the above-mentioned two types of drills are opposed to each other on both sides of the workpiece on the same axis. Position and advance the two drills to start drilling from both sides of the workpiece. Before the two drills hit, stop the advancement of one of the drills and retract this drill to a position where it cannot be removed from the workpiece A through hole drilling method, wherein only the other drill is advanced to penetrate the holes from both sides of the workpiece. The drilling method for a through hole according to claim 1, wherein a cutting oil supply pressure of a drill that is retreated in the middle is higher than a cutting oil supply pressure of the other drill.

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