JPS60259303A - Deep-hole cutting apparatus - Google Patents

Abstract

PURPOSE:To reduce the amount of coolant and increase cutting-speed by arranging a nozzle in the spiral direction so that the coolant jetted-out from an ejector nozzle performs eddy-current movement in the hollow part of a tool shank. CONSTITUTION:The coolant supplied from a high-pressure coolant feeding source is jetted-out in the spiral direction with respect to the axis center of a tool shank 16 and a discharge pipe 26 through a jet nozzle 27 from a jacket 25 and discharged in the form of eddy current. Therefore, the hollow part 20 of the tool shank is made vacuum, and the coolant is inhaled into a cut hole 14 through a boring-head opened port 19 through vacuum aspiration and eddy-current vacuum. Therefore, the cooling effect and the chip 15 discharging capacity can be improved, and high-speed cutting is permitted.

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 joint system. The present invention relates to an improvement in a deep hole cutting system, which is a system for discharging chips generated during deep hole cutting from a cut hole using a vacuum effect.

First, a conventional example will be explained with reference to FIG. 3. A double tube consisting of an outer tube 1a and an inner tube 1b is used for the tool shank 1, and a boring head 3 having a cutting edge 2 on the outer tube 1a at the tip of the tool shank 1. A coolant outlet 5 that communicates the gap 4 between the outer tube la and the inner tube 1b is formed on the side surface of the boring head 3, and an inner tube is also attached to the tip of the boring head 3. An opening 7 communicating with the hollow portion 6 is formed.

A discharge pipe 9 coaxially communicating with the inner tube 1b is connected to the base of the tool shank 1 via a joint body 8, and the joint body 8, which is fitted and fixed to the tool shank 1, has an outer tube la and an inner tube 1b. A coolant pressure inlet 10 communicating with the gap 4 is provided, and ejector nozzles 11 are provided in the inner tube 1b at appropriate intervals in the circumferential direction at positions facing the coolant pressure inlet 10. In use, while rotating either the tool shank 1 or the workpiece 12, the boring head 3 of the tool shank 1 is placed against the workpiece 12 to perform drilling and cutting, and at the same time, high-pressure coolant 13 is supplied from the high-pressure coolant supply source □ to increase the coolant pressure. A portion of this high-pressure coolant is fed into the gap 4 between the outer tube 1a and the inner tube 1b from the inlet 10, flows through the gap 4, reaches the Pauling Rad 3, and is passed through the coolant outlet 5.
It flows into the cutting hole 14 and reaches the cutting edge 2, where the pressure becomes the same as atmospheric pressure. On the other hand, the high-pressure tarant is ejected from the gap 4 through the ejector nozzle 11 into the inner tube 1b, 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 acts on the cut hole 14 through the boring head opening 7, and the coolant flowing into the cut hole 14 is The boring head opening 7 is opened by the above suction force.
Chips 15 flowing into the inner tube hollow part 6 from the coolant and generated in the cutting hole 14 are discharged to the outside through the inner tube hollow part 6 together with this coolant, and this discharge accelerates the cutting process of the boring head 3. . The ejector nozzle conventionally formed in the inner tube 1b is elongated in the circumferential direction of the tube as shown in FIG. In order to generate a sufficient vacuum effect, extremely high-pressure coolant had to be fed into the inner tube 1b through the pressure inlet 10.For example, the hole diameter was 26f.
In order to form a drill hole of iφ, the conventional type of cutting device shown in FIG. 3 requires a hydraulic pressure of 17 kg/cd, resulting in a cutting speed of 200 fi/min.

The present invention uses less coolant oil pressure than the conventional apparatus described above (and increases the cutting speed).

One embodiment of the present invention will be described below with reference to FIGS. 1 and 2. Reference numeral 16 denotes a tool shank consisting of a cylindrical boring bar, to which a boring head 18 having a dividing blade 17 at the tip is attached. 18 communicates the hollow part 20 of the tool shank 16 with the outside through its opening 19. Reference numeral 21 denotes a coolant jacket that is slidably fitted on the tip side of the tool shank 16, and this jacket 21 has a sealing material 22 attached to the material 12.
At the tool shank insertion portion of this jacket 21, a sealing material 23 is interposed between the jacket 21 and the tool shank 16 at the insertion portion on the side opposite to the material 12 side. In addition to preventing the coolant 13a supplied to the
A coolant pressure feeding port 24 is provided around the tool shank 16 at the insertion portion on the workpiece 12 side, so that the coolant 13a supplied to the jacket 21 flows through the coolant pressure feeding port 24 to the workpiece 12 side. Reference numeral 25 denotes another coolant jacket fitted and fixed to the base end of the tool shank 16. A discharge pipe 26 coaxially communicating with the tool shank 16 is connected to this jacket 25. Ejector nozzles 27 for ejecting the coolant 13b under pressure into the discharge pipe 26 are opened at regular intervals in the circumferential direction, and the ejector nozzles 27 are connected to the tool shank 16 and the ejector nozzles 27 as shown in FIG. With respect to the axis of the discharge pipe 26! I! I rotation direction is fixed.

In use, the boring head 18 of the tool shank 16 is placed against the workpiece 12 while either the tool shank 16 or the workpiece 12 is rotated, and at the same time, high-pressure coolant is supplied from a high-pressure coolant supply source. 1
3a, 13b are fed into the jacket 21.25. The high-pressure tarant 13a supplied to the jacket 21 flows into the cutting hole 14 that is being cut from the coolant feeding port 24 of the jacket 13a, passes through the gap 28 between the outer surface of the tool shank 16 and the inner surface of the cutting hole 14, and is applied to the cutting edge 17 under pressure. leading to. On the other hand, the high pressure coolant 1 supplied to the jacket 25
3b is ejected under pressure from the ejector 7 female 27 into the discharge pipe 26 and is discharged to the outside through the discharge pipe 26. At this time, the ejector nozzle 27 is opened in a helical direction with respect to the axes of the tool shank 16 and the discharge pipe 26. With this discharge, the hollow part 20 of the Che/R shank is evacuated, and the suction force due to this vacuum and the vortex movement passes through the boring head opening 19 and into the cutting hole 14. Therefore, the high-pressure coolant 13a that has reached the cutting edge 17 closes the opening 19 of the boring head 18 due to the synergistic effect of its own pressure, i-power, and the suction force that acts through the tool shank hollow section 20. The chips 15 that flow into the hollow part 2o of the threading tool shank and are generated in the cutting hole 14 also flow into the hollow part 20 of the tool shank along with the flow of this high-pressure coolant 13a, and are transferred to the outside together with the high-pressure coolant 13a. This discharge further facilitates the cutting of the boring head 18.

The high-pressure coolant thus ejected from the ejector nozzle 27 into the tool shank hollow portion 20 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 hollow portion 20, but together with this, the vortex flow is generated according to the so-called vortex flow theory (
It is known that, according to the vortex theory, the speed of the vortex increases as it approaches the center of the vortex, and a stronger suction force is generated at the center. Therefore, a stronger suction force is generated in the hollow portion 20 in the ejection 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 ejected together with the coolant even more rapidly. For example, as a result of experiments, in order to drill a 26 m drill hole using the cutting device shown in this example, the cutting speed can be increased to 360 m by simply feeding 10 kg/ci hydraulic coolant into both jackets 21.25.
Compared to the conventional device mentioned above,
Even though the coolant oil pressure is low, the cutting speed is significantly higher.

As described above, according to the present invention, a pair of high-pressure coolant supply jackets are provided on the outer periphery of a cylindrical tool shank having a boring head attached to its tip, and one of the jackets surrounds the cylindrical tool shank in an oil-tight manner. The high-pressure coolant supply jacket is designed to pump the coolant provided in contact with the end surface of the workpiece through the gap between the inner surface of the cutting hole and the outer surface of the tool shank, and to the cutting edge of the boring head. - The high-pressure coolant supply jacket is equipped with an ejector nozzle that communicates with the hollow part of the tool shank, and in a deep hole cutting device, the ejector axis is By forming an opening in a spiral direction, an extremely high suction force is generated in the direction of ejecting the hollow part of the tool shank due to the vacuum effect due to the jetting of high-pressure coolant from the ejector nozzle and the suction effect due to the violent vortex movement of the coolant, which facilitates chip evacuation. The capability has been dramatically improved, and the feed rate of the tool system has increased accordingly, making it possible to perform high-efficiency cutting of deep holes.

In particular, according to the present invention, by using a thick high-pressure coolant supply jacket, the opening distance in the spiral direction in which the ejector nozzle is provided can be formed with a sufficient margin, and the vortex flow caused by the coolant can be formed. can be caused well.

[Brief explanation of the drawing]

Fig. 1 is a schematic cross-sectional configuration diagram of a deep hole cutting device other than the embodiment of the present invention, Fig. 2 is an enlarged cross-sectional view taken along the line II- The configuration diagram and FIG. 4 are perspective views showing the main parts of this type of conventional device. 12... Workpiece, 14... Cutting hole, 15... Chips, 16... Tool shank, 17... Cutting edge portion,
18... Polling head rad, 20... Tool shank hollow part, 19... Boring head opening, 21.2
5... Jacket for high pressure coolant supply, 27...
ejector nozzle.

Claims (1)

[Claims] A pair of high-pressure coolant supply jackets are provided on the outer periphery of the cylindrical tool shank, which has a boring head attached to its tip, and which oil-tightly surrounds the cylindrical tool shank. The coolant provided in contact with the end surface of the object is forced to be fed to the cutting edge of the boring head through the gap between the inner surface of the cutting hole and the outer surface of the tool shank, and the other high-pressure coolant supply jacket is connected to the tool shank. In a deep hole cutting device that is equipped with an ejector nozzle that communicates with a hollow part and is configured to eject coolant from the ejector nozzle into the hollow part of a tool shank, the coolant ejected by the ejector nozzle flows into the hollow part of the tool shank. A deep hole cutting device characterized in that the ejector nozzle is formed as an opening in the jacket in a helical direction with respect to the tool shank axis so that the ejector nozzle is ejected while generating a vortex movement inside the jacket.