JPH0724609A - Deep hole cutting tool - Google Patents

Abstract

PURPOSE:To surely discharge chips even in the case of hole machining where a ratio of length to a diameter in the cut hole is larger than a specified value, by forming a spiral groove having height smaller than the diameter of the cut hole and width larger than a diameter of a boring bar in the outer periphery of the boring bar. CONSTITUTION:An SCM round bar, for example, a little longer than about 600mm is used as a boring bar 54. In the outer periphery of the boring bar 54, a thin iron plate 60 of plate thickness about 1,5mm is fixed by welding in a spiral shape at a pitch of about 100mm and with height of about 14mm in the direction reverse to the tool turning direction viewed from an inner cutting edge 51 side, that is, the direction advancing to the opposide side of the inner cutting edge 51 when the spiral is traced in the tool turning direction. Namely, width of a groove 71 for inducing chips is formed about 97mm. Chips produced by cutting of the inner cutting edge 51 and outer cutting edge 52 are discharged via the spiral shape groove 71. When a tool of this type wherein a ratio of length to a diameter in a cut hole is 5 and groove width is equal to the outer periphery of the boring bar 54 is manufactured, cutting in the vertical and horizontal directions can be excellently performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a deep hole cutting tool for making holes in which the ratio of the length of the cutting hole to the diameter of the cutting hole is 5 times or more.

[0002]

2. Description of the Related Art FIG. 2 is an explanatory view of a conventional example of a deep hole cutting tool. The chip 1 is fixed to the head 3, and the head 3
Is attached to the boring bar 4. When the boring bar 4 is rotated, the tip 1 is rotated accordingly and the workpiece 2 is cut. The annular pressure head 6 is pressed against the work piece 2, and the pressure head 6 and the work piece 2 and the pressure head 6 are pressed together.
The O-rings 9 and 10 seal between the boring bar 4 and the boring bar 4. The pressure head 6 is provided with a cutting oil inlet 7. A spiral groove 5 is provided on the inner surface of the boring bar 4, and the groove 5 is opposite to the tool rotating direction when viewed from the tip 1 side. That is, when the spiral is traced in the tool rotation direction, it is a direction in which the spiral advances to the side opposite to the tip 1.
The groove 5 may be provided over the entire length of the boring bar 4 or may be partially provided.

The operation of FIG. 2 will be described. The cutting oil supplied from the cutting oil inlet 7 reaches the tip 1 through the space between the inner wall of the hole formed in the work 2 and the boring bar 4 and the head 3, as shown by the arrow in FIG. Lubricate and cool 1. Next, the cutting oil flows through the inner peripheral portion of the boring bar 4 and is discharged from the end 8 of the boring bar 4 to the outer peripheral portion. At that time, chips generated by cutting with the chip 1 are also discharged to the outside through the inner peripheral portion of the boring bar 4 at the same time. When the machining efficiency is increased and the amount of chips produced increases, it becomes impossible to flow the chips out by the pressure of the cutting oil, and the chips are clogged in the inner peripheral portion of the boring bar 4 to make it impossible to machine.
In the structure of FIG. 2, since the spiral groove 5 is provided in the inner peripheral portion of the boring bar 4 as described above, the screw effect of the groove 5 increases the flow velocity of the cutting oil, and as a result, the chip discharging capability is improved. Is.

Since the spiral groove 5 is provided on the inner peripheral surface of the boring bar 4 of the tool in the direction opposite to the tool rotating direction when viewed from the tip 1 side, the screw effect of the groove 5 increases the flow velocity of the cutting oil. As a result, even if the chip discharge capacity is increased and the amount of generated chips is increased, the chips can be surely discharged.

Another conventional example will be described with reference to FIG. As shown in FIG. 3, in this example, in addition to the structure shown in FIG. 2, a spiral groove 11 is provided on the outer peripheral portion of the boring bar 4. The direction of the spiral groove 11 is opposite to that of the spiral groove 5 on the inner peripheral side. As a result, the flow velocity of the cutting oil until it reaches the tip 1, that is, while passing through the gap between the work piece 2 and the outer circumference of the boring bar 4, is increased by the screw effect of the groove 11 on the outer circumference side, It is possible to increase the inflow pressure of cutting oil to the portion and the subsequent chip discharge pressure, and improve the machining efficiency.

On the other hand, instead of the chips passing through the inner peripheral portion of the boring bar as shown in FIGS. 2 and 3, there is a deep hole machining tool 21 for discharging the chips along the lead of the tool as shown in FIG. Figure 4
The deep hole processing tool 21 shown in is a processing tool in which the total length and groove length of the JIS standard Morse taper shank drill are increased.
Simultaneously with rotation, it moves in the axial direction to perform cutting. The chips are discharged along the leads of the groove portion 22. However, if the ratio of the length of the cutting hole to the diameter of the cutting hole exceeds five times, chips cannot be discharged in the two-fold spiral groove (helix angle of about 30 degrees), and the deep hole machining tool 21 is temporarily removed from the cutting hole. To discharge the chips, return the deep hole drilling tool 21 to the original position again, and perform cutting. Every time the chips are collected in the groove 22, the deep hole drilling tool 21
Repeatedly take out to process.

[0007]

With any of the above-mentioned cutting tools, it is very difficult to make a hole in which the ratio of the length of the cutting hole to the diameter is 5 times or more, particularly, to make a hole in the longitudinal direction. Has become. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a deep hole cutting tool that can easily perform hole drilling in which the ratio of the length to the diameter of the cutting hole is 5 times or more.

[0008]

The structure of the present invention for achieving the above object is a deep hole cutting tool for making a hole having a ratio of the length of the cutting hole to the diameter of the cutting hole of 5 times or more. A spiral groove having a height smaller than the diameter of the cutting hole and a width equal to or larger than the diameter of the boring bar is formed on the outer periphery of the boring bar.

[0009]

[Operation] The object to be cut is cut by the rotation of the boring bar. The cut chips are guided to a spiral groove having a width smaller than the diameter of the cutting hole and not less than the diameter of the boring bar to be discharged.

[0010]

1 is a perspective view of a deep hole cutting tool according to an embodiment of the present invention. The illustrated deep hole cutting tool forms a deep hole having a diameter of 60 mm and a length of 600 mm, for example.
That is, a deep hole in which the ratio of the length of the cutting hole to the diameter of the cutting hole is 10 times is cut.

At the end of the drill head 53, an inner blade 51 and an outer blade 52 (shown in the removed state) are fixed,
A pilot drill 55 is attached to the tip of the central portion of the head 53.
(The figure shows the removed state). Furthermore, the diameter of the cutting hole (60 mm) is provided on the outer peripheral portion of the boring bar 54.
In the present embodiment, the super hard guide pad 56 is attached so as to have a diameter slightly smaller than the outer diameter by 5/100 mm so as to have a slightly smaller diameter. The drill head 53 is attached to the boring bar 54,
An annular drive ring 57 is installed between the drill head 53 and the drill head 53.
Is attached. When the boring bar 54 is rotated, the inner blades 51 and the outer blades 52 are rotated accordingly and cutting is performed. The drive ring 57 is pressed against the object to be cut, and the pressure oil that has entered from an oil filling port (not shown) is pressed into the tip portion through the outer peripheral portion of the drill head 53, and the through hole 58 is formed.
Is discharged through a through hole formed in the boring bar 54.

As the boring bar 54, a round bar of SCM, which is slightly longer than 600 mm, is used. On the outer periphery of the boring bar 54, a thin iron plate 60 having a thickness of 1.5 mm is spirally formed with a pitch of 100 mm and a height of 14 m.
It is fixed by welding in a direction opposite to the tool rotation direction when viewed from the side of the inner blade 51 at m, that is, in a direction in which the spiral advances in the direction opposite to the inner blade 51 when tracing the tool rotation direction. That is, the width of the groove 71 that guides the cutting waste is formed to about 97 mm.

Next, the operation of the deep hole cutting tool shown in FIG. 1 will be described. The cutting oil supplied from the cutting oil inlet (not shown) is used for the inner wall of the hole formed in the work and the boring bar 54.
And the inner blade 51 and the outer blade 5 are passed through between the drill head 53 and the drill head 53.
2, the inner blade 51 and the outer blade 52 are cooled by lubrication. Next, the cutting oil flows from the through hole 58 through the inner peripheral portion of the boring bar 54 (not shown) and is discharged from the end of the boring bar 54 to the outer peripheral portion. At this time, the chips generated by the cutting with the inner blade 51 and the outer blade 52 have a gap of about 97 mm on the outer peripheral surface of the boring bar 54 in the thin iron plate 60 in the direction opposite to the tool rotation direction when viewed from the inner blade 51 and the outer blade 52 sides. Since the spiral groove 71 is formed, chips are discharged through the groove 71 without resistance.

The ratio of the length of the cutting hole to the diameter of the cutting hole is 5
It has been confirmed that even if the width of the groove 71 is made the same as the outer circumference of the boring bar 54 and is cut in the horizontal and vertical directions, the groove 71 can be satisfactorily cut. Although cutting oil is used in the above embodiment, chips are satisfactorily discharged even when cutting oil is not used.

[0015]

In the deep hole cutting tool of the present invention, since the spiral groove having a height smaller than the diameter of the cutting hole and a width not less than the diameter of the boring bar is formed on the outer periphery of the boring bar,
Even if a hole having a ratio of the length to the diameter of the cutting hole of 5 times or more is drilled, the cutting waste can be reliably discharged. As a result, it is possible to satisfactorily cut a hole having a length to diameter ratio of 5 times or more. Moreover, the deep-hole cutting tool of the present invention is easy to manufacture, and can cut well even a deep hole in the vertical direction.

[Brief description of drawings]

FIG. 1 is an overall perspective view of a deep hole cutting tool according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional deep hole cutting tool.

FIG. 3 is a cross-sectional view of a conventional deep hole cutting tool.

FIG. 4 is a side view of a conventional deep hole cutting tool.

[Explanation of symbols]

 51 Inner Blade 52 Outer Blade 53 Drill Head 54 Boring Bar 55 Pilot Drill 56 Guide Pad 60 Thin Iron Plate 71 Groove

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Teruo Akiyama 1-26-15 Tomioka, Koto-ku, Tokyo Inside Japan Heltel Co., Ltd.

Claims (1)

[Claims] 1. A deep-hole cutting tool for making a hole in which the ratio of the length of the cutting hole to the diameter of the cutting hole is 5 times or more, the height being smaller than the diameter of the cutting hole, and the width being the diameter of the boring bar. A deep hole cutting tool characterized in that the spiral groove as described above is formed on the outer periphery of a boring bar.