JPS6116562B2 - - Google Patents

Description

[Detailed description of the invention] In deep hole machining, the ability to discharge chips generated inside the cutting hole to the outside determines the deep hole cutting speed. In both cases, no improvement in deep hole cutting speed can be expected. Therefore, various chip evacuation methods have been devised, and
This chip evacuation method is called a deep hole machining system. Among such deep hole cutting systems, the present invention particularly relates to an improvement of a deep hole cutting device, which is a system for discharging chips generated during deep hole cutting from a cutting hole using a vacuum effect.

First, a conventional example will be explained using FIG. 1 showing an embodiment of the present invention.A double tube consisting of an outer tube 1a and an inner tube 1b is used for the tool shank 1. A boring head 3 having a cutting edge 2 is attached to 1a, and a coolant outlet 5 is formed on the side surface of the boring head 3 to communicate the gap 4 between the outer tube 1a and the inner tube 1b. Inner tube hollow part 6 at the tip of head 3
An opening 7 communicating with is formed. A discharge pipe 9 is connected to the base of the tool shank 1 via a joint body 8 and coaxially communicates with the inner tube 1b.
A joint body 8 fitted and fixed to the tool shank 1 is provided with a coolant inlet 10 that communicates with the gap 4 between the outer tube 1a and the inner tube 1b, and a coolant inlet 10 is provided in the inner tube 1b at a position opposite to the coolant inlet 10. Ejector nozzles 11 are provided at appropriate intervals in the circumferential direction. In use, while either the tool shank 1 or the material 12 is rotated, the boring head 3 of the tool shank 1 is brought into contact with the material 12 to perform drilling and cutting, and at the same time, high-pressure coolant 13 is supplied from the high-pressure coolant supply source. A part of this high-pressure coolant is fed into the gap 4 between the outer tube 1a and the inner tube 1b from the pressurization port 10, flows through the gap 4, reaches the boring head 3, and flows into the cut hole 14 from the coolant outlet 5. The pressure reaches the cutting edge 2, where the pressure becomes the same as atmospheric pressure. On the other hand, the high-pressure coolant passes through the ejector nozzle 11 from the gap 4 to the inner tube 1.
b, and is discharged from the inner tube 1b to the outside through the discharge pipe 9. The inner tube hollow part 6 is evacuated by the ejector effect when ejected from the ejector nozzle, and the suction force due to this vacuum is applied to the boring head opening 7.
The coolant flowing into the cutting hole 14 flows from the boring head opening 7 into the inner tube hollow portion 6 by the suction force.
Chips 15 flowing into the cutting hole 14 and generated in the cutting hole 14
Together with this coolant, the coolant is discharged to the outside through the inner tube hollow part 6, and this discharge facilitates the cutting process of the boring head 3.

As mentioned above, the conventional device also uses the ejector nozzle 11.
The configuration is the same as that of this embodiment except for the configuration.

By the way, the ejector nozzle conventionally formed in the inner tube 1b is a slit-shaped nozzle 16 that is elongated in the circumferential direction of the tube as shown in FIG. In order to produce the effect, very high pressure coolant had to be pumped into the interior of the inner tube 1b through its injection port 10. For example, hole diameter 26mmφ
In order to form a drill hole of 17 kg/cm ² in a cutting device of the type shown in FIG. 1, a cutting speed of 200 mm/min is required.

The present invention is designed to require less coolant oil pressure than the conventional device described above, and to increase the cutting speed.

In order to achieve the above object, the present invention provides circular holes arranged in a helical direction with respect to the axial center at appropriate intervals in the circumferential direction in the inner tube 1b at a position facing the coolant inlet 10, as shown in the embodiment shown in FIG. A shaped ejector nozzle 11 is opened.

Therefore, the high-pressure coolant ejected from the ejector nozzle 11 into the inner tube 1b is discharged while generating a violent swirling motion along the tube wall. This ejection of high-pressure coolant naturally generates a suction force within the inner tube 1b, but at the same time, the speed of the vortex increases as it approaches the center of the vortex, according to the so-called vortex theory. It is known that a stronger suction force is generated in the center. Therefore, a stronger suction force is generated in the inner tube 1b in the discharge direction due to the vacuum effect due to the ejector nozzle effect and the suction force due to the vortex movement, and the chips 15 are discharged together with the coolant at an even faster rate. become. For example, as a result of experiments, in order to drill a 26 mmφ drill hole with the type of cutting equipment shown in Figure 1, the cutting speed can be increased to 320 mm by simply feeding 10 kg/cm ² of hydraulic coolant into the inner tube 1b from the pressurizing port 10. /min, and the cutting speed is much higher than that of the conventional device described above, even though the coolant oil pressure is low.

As described above, according to the present invention, when drilling and cutting a hole in a workpiece using a boring head attached to the tip of a cylindrical tool shank consisting of a double tube including an outer tube and an inner tube, the gap between the two tubes is The coolant flows into the cutting hole through the inner tube, and is also jetted into the hollow part of the tool shank through the ejector nozzle provided in the inner tube, thereby flowing into the cutting hole through the hollow part of the tool shank and the boring head opening. In a device that applies a suction force to suction and discharge the chips cut by the boring head together with the coolant flowing into the cutting hole, the ejector nozzle is arranged in the inner tube in a helical direction with respect to the axis of the tool shank. By doing so, an extremely high suction force is generated in the direction of ejection from the hollow part of the tool shank due to the vacuum effect caused by the jetting of high-pressure coolant from the ejector nozzle and the suction effect caused by the violent vortex motion of the coolant, dramatically increasing the chip evacuation ability. As a result, the feed rate of the tool system increases, making it possible to cut deep holes with high efficiency.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional configuration diagram of a deep hole cutting device showing a first embodiment of the present invention, Fig. 2 is an enlarged view taken along the line - - in Fig. 1, and Fig. 3 is a main part of a conventional device of this kind. FIG. 1...Tool shank, 1a...Outer tube,
1b...inner tube, 3...boring head, 4...opening, 6...tool shank hollow part, 7...boring head opening, 11...ejector nozzle, 12...workpiece, 14...cutting hole, 15...chips.

Claims (1)

[Claims] 1. When drilling and cutting a hole in a workpiece using a boring head attached to the tip of a cylindrical tool shank consisting of a double tube consisting of an outer tube and an inner tube, coolant is injected into the cut hole through the gap between the two tubes. At the same time, the coolant is also injected into the hollow part of the tool shank through the ejector nozzle provided in the inner tube, thereby exerting a suction force into the cutting hole through the hollow part of the tool shank and the boring head opening, thereby causing the coolant to flow into the cutting hole. In this device, the ejector nozzle is connected to the tool shank so that the coolant ejected by the ejector nozzle is discharged while causing a whirlpool movement within the hollow part of the tool shank. A deep hole cutting device characterized in that the inner tube is opened in a spiral direction with respect to the axis of the inner tube.