JP6635574B2 - Drill or gun drill - Google Patents

Description

  The present invention provides a coolant ejection hole in a chip discharge groove portion on the tip end side of a drill, and supplies coolant at a high pressure from the ejection hole to a contact portion between a cutting tip and a work material, thereby providing a chip. The present invention relates to a U-drill or a gun drill which cools a cutting edge surface and chips, and separates and discharges chips, thereby increasing a feed speed of a drill and enabling efficient cutting.

  Conventionally, when drilling holes in light alloys such as aluminum or steel materials, drills are used to prevent damage to the drill due to heat generated due to friction between the cutting edge of the drill and the work material and extend the life of the drill. Coolant ejection holes are provided on the tip side. Then, coolant supplied through a coolant supply passage provided through the main shaft of the drill is ejected from the ejection hole. Drills for machine tools include a twist drill in which a coolant supply passage is twisted similarly to the main shaft, and a straight drill that is not twisted during manufacturing.

  FIG. 3 shows a conventional U drill in which a main shaft 1 and a coolant supply passage 2 are twisted and formed. In the U-drill, the tip of the spindle 1 is formed on a flat surface 3, and a tip 6 as a cutting blade is attached to a vertical wall surface 5 connected to a chip discharge groove 4 so that the tip 6 projects from the flat surface 3 at the tip of the spindle. I have. The coolant is ejected from an ejection hole 7 opened in the flat surface 3 at the tip of the spindle through the coolant supply passage 2 twisted in the spindle. The U-drill shown in FIG. 3 is of a type in which the tip 6 can be replaced, and there is another type in which the tip is fixed.

On the other hand, at present, the coolant is supplied at a pressure of less than 7 MPa as a coolant supply pressure for this type of twist drill. The reasons for this are unknown, but there are no support for machine tools, no holder tool, and no data of 7 MPa or more. As an exception, as shown in Patent Literature 1, in consideration of a large pressure loss in the case of drilling a small hole, the gas is ejected at a high pressure of about 10 MPa to 14 MPa.

JP 2004-042209 A

  In the conventional U drill, as described above, the coolant is ejected from the ejection hole 7 opened in the flat surface 3 at the tip of the spindle, through the coolant supply passage 2 having the twisted spindle portion. Since this squirt is only squirted toward the front side of the main shaft, the squirt is squirted from above the swarf of the work material shaved by the cutting blade, so that the tip 6 as the cutting blade is It is not supplied to the parts that are in direct contact with. Therefore, there has been a problem that the temperature of the tip 6 becomes high due to friction with the work material, deformation and wear occur, and the life is shortened.

  Further, in the technique disclosed in Patent Document 2 and the like, the supply pressure of the coolant is set to 10 MPa or more and about 14 MPa. However, this is for the case of fine hole drilling, and in general hole drilling, the pressure is less than 7 MPa. there were. For this reason, the supply of coolant to the processing site is insufficient, and the cooling of the cutting blade and the discharge of chips have been insufficient. Therefore, conventionally, after drilling several millimeters, the drill is once retracted to cool the cutting blade and discharge chips, and then the drill is further advanced to perform cutting. It is common practice to drill a hole repeatedly, which is inefficient.

  In addition, if the supply pressure is less than 7 MPa, the chip breaking effect is lacking, so that chips are continuously generated up to a considerably long dimension, and the chips may not be smoothly discharged from the discharge groove of the drill. there were. In addition, long chips may be wound around the drill and damage the drill and the work material. In addition, long chips are bulky and difficult to be stored in any desired form, which may be difficult to treat.

  The problem of cooling the cutting blade and the work material and the problem of chip processing were the same for gun drills other than the U drill.

The present invention has been improved and eliminated in view of the above-mentioned conventional problems, and has an excellent coolant of a chip and a work material by directly supplying coolant to a portion where the chip and the work material are in contact with each other. Due to the synergistic effect of cooling and supplying the coolant to the above-mentioned portion and increasing the supply pressure thereof, fine cutting of chips can be realized, and discharge of chips and subsequent processing can be facilitated. there is provided cents U drill or gun drill.

Hand stage to which the present invention is adopted to solve the above problems, the distal end surface of the drill body is formed flat, chip drill or gun drill attached to the drill body as the cutting edge faces the said flat surface , A coolant ejection hole is provided on the chip discharge groove surface, and the direction of the communication passage connected to the coolant supply passage and the inclination angle of the discharge groove surface are determined by the coolant ejected from the discharge hole. Is set so as to be jetted directly toward the cutting edge of the tip , and a coolant jetted at a high pressure of 7 MPa or more and 30 MPa or less is jetted directly to a contact portion between the tip and the work material, and the A drill or a gun drill characterized in that the work material is processed while cutting chips shaved from the material .

Moreover, in this drill, the ejection hole of the coolant jet nozzle to increase the jet momentum and an orifice is that attached detachably.

According to the present invention , the coolant ejection hole is provided on the chip discharge groove surface. Then, the direction and angle of the coolant ejected from the ejection holes are ejected toward the cutting blade. If necessary, the chip discharge groove surface may be ground so as to have a desired direction and angle. Thereby, the coolant can be supplied directly to a portion where the tip as a cutting blade and the work material come into contact. Therefore, the effect of cooling the tip and the work material is excellent, and it is possible to suppress the wear of the tip and extend the life thereof. As a result, the processing speed can be increased, and excellent and efficient drilling can be performed. Further, since the coolant is supplied to a portion where the chip and the work material are in direct contact, there is also an effect that the shaved chips are easily cut in a short dimension.

Further, detachably mounted lever the jet nozzle jetting hole of the coolant, the nozzle has an orifice, you jetting a strong water force to compress the supplied coolant. Thereby, the effect of cooling the chip and the work material and the effect of cutting off the chips are further improved.

Further, the coolant is ejected at a high pressure of 7 MPa or more and 30 MPa or less. Thus, click Zealand is supplied to the contact portion between the tip and the workpiece, further because the supply pressure is extremely high as described above, chips which are scraped from the workpiece at the stage of very short dimension It is immediately separated and flows into the discharge groove together with the coolant, and is smoothly discharged out of the drill from the discharge groove. Since the chips are cut into extremely short dimensions in this manner, the chips easily pass through the discharge groove existing around the main shaft. After leaving the drill, it can be stored in a container of any shape, and the processing is easy.

It is a perspective view of the tip part of the U drill concerning a 1st embodiment of the present invention. It is a partial longitudinal section side view showing the tip of the main shaft of the U drill according to the first embodiment of the present invention. FIG. 2 is an enlarged vertical sectional view showing a jet injection nozzle attached to a coolant ejection hole of the U drill according to the first embodiment of the present invention. It is a perspective view of the tip part of the conventional U drill.

Hereinafter, the configuration of the present invention will be described based on one embodiment of the twisted U drill shown in FIGS. 1 to 3 as follows. The U-drill refers to a drill having a flat tip surface and a detachable tip . As shown in FIG. 1, the drill of this embodiment is a twist formed of high-speed steel or cemented carbide. This is a U-drill of the type, and a total of two pieces, a central blade and an outer peripheral blade, are attached to a portion of the vertical wall surface 5 connected to the chip discharge groove surface 4 at a position where the chip 6 is symmetrical. These chips 6 are provided so that they can be replaced by screws.

In this embodiment, a coolant ejection hole 8 is provided in the chip discharge groove surface 4. The ejection hole 8 has a communication passage 9 connected to the coolant supply passage 2. The ejection holes 8 and the communication passages 9 are formed after the discharge grooves 4 and the coolant supply passages 2 of the main shaft (drill body) 1 are twisted to form a continuous spiral. At this time, as shown in FIG. 2, the direction and the inclination angle of the communication passage 9 are set so that the coolant ejected from the ejection hole 8 is ejected toward the cutting edge surface of the tip 6.

  What is important when forming the coolant ejection hole 8 and the supply passage 9 is that the coolant supply passage 2 is formed with the same twist angle as the twist of the main shaft, so that the coolant is supplied through the coolant supply passage 2. In order to determine the angle at which the coolant is ejected from the ejection hole 8 so as to be ejected toward the contact portion between the cutting edge surface of the insert 6 and the work material, the twist state of the supply passage 2 is grasped. This is very important.

  That is, in the case of the twisted U drill, the coolant supply passage 2 is also formed by being twisted, so that merely providing the opening of the ejection hole 8 in the chip discharge groove 4 causes the cutting edge surface of the chip 6 to be covered. This is because the coolant is only ejected toward the vicinity of the portion where the workpiece comes into contact with the workpiece, and the chip 6 cannot directly supply the workpiece to the location where the workpiece is being cut. If such a condition is not satisfied, the chip discharge groove 4 is cut and the twist direction of the coolant supply passage 2 in the main shaft portion meshes with the inclination angle of the chip discharge groove 4 so that the coolant is removed. The position directly supplied to the contact portion between the workpiece and the work material is specified.

  By specifying the opening position of the coolant ejection hole 8 and the direction and the inclination angle between the ejection hole 8 and the communication passage 9 of the coolant supply passage 2 in this manner, the chip 6 and the work material directly contact each other in this embodiment. Coolant can be supplied to the part where it is performed. Therefore, the cooling effect is excellent, and it is possible to suppress the wear of the cutting edge surface of the insert 6 and extend the life thereof. As a result, the processing speed can be increased, and excellent and efficient processing can be performed. It was possible to machine at a speed 7 times or more as compared with the conventional machining method in which forward and backward movements were repeated.

  A jet injection nozzle (plug) 10 is detachably attached to the coolant ejection hole 8 by a screwing method. The nozzle 10 has a detachable hexagonal hole (a square or other polygonal hole or a star-shaped hole) 11 provided on the front end surface, and a conical tapered hole for narrowing the coolant on the rear end surface side. 12 are provided. An orifice 13 is formed at a portion connecting the hexagonal hole 11 and the tapered hole 12. A screw portion 14 is provided on the outer peripheral surface of the nozzle 10. A hexagon wrench is inserted into the hexagonal hole 11 and the whole nozzle 11 is rotated, so that the screw is screwed into or removed from the ejection hole 8. I can do it.

  Accordingly, the coolant is compressed by the tapered hole 12 of the nozzle 10 to increase the water force, and is jetted toward the cutting edge surface of the tip 6 in a jet jet state by passing through the orifice 13. By this jet injection, the chips of the work material that are shaved off by the tip edge surface are turned up by the strong water force of the jet injection, and the coolant can be supplied directly to the edge surface.

  Further, in the present invention, the pressure of the coolant jetted from the jet jet nozzles 10 of each jetting hole 8 is set to 7 MPa or more and 30 MPa or less using a high-pressure pump manufactured in-house. Thereby, the coolant injected from the jet injection nozzle 10 is directly supplied to the contact portion between the chip 6 and the work material, so that the chips immediately after being cut off from the work material are turned up. Increase. In addition, the chips are immediately separated at extremely short steps by the coolant jetted at a high pressure, flow into the chip discharge grooves 4 together with the coolant, and are smoothly discharged from the discharge grooves 4 to the outside of the drill.

  Actually, the relationship between the coolant supply pressure and the size of the chips when the material of SCM415 (chromium molybdenum steel) is turned with a lathe is as follows. When the supply pressure of the coolant is 2 MPa, the length of the chip is 50 mm or more, when it is 7 MPa, it is cut about 30 mm, when it is 10 MPa, it is divided into about 15 mm, and when it is 15 MPa, it is about 7 mm. The size was about 5 mm at 20 MPa, about 3 mm at 25 MPa, and about 3 mm at 30 MPa.

  Since the chips are cut into extremely short dimensions in this manner, the chips easily pass through the discharge groove 4 which is twisted around the main shaft. After being discharged from the drill, it can be stored in a container of any shape, and the processing is easy. This makes it possible to use an autoloader that automatically discharges chips, thereby greatly improving the workability of cutting.

By the way, the present invention is not limited to the embodiment of the U-drill, and can be applied to a gun drill in which a chip discharge groove is formed straight. In this gun drill, the pressure of the supplied coolant is not less than 7 MPa and not more than 30 MPa. Therefore, even if the length of the gun drill itself is long, the straightness of the drill itself is increased by the high water pressure of the coolant, and the deep hole drilling is improved. There is also an effect that the finishing can be performed with high precision.
Although the jet injection nozzle detachably attached to the coolant ejection hole is described as a screw-in type, it may be a press-fit type. In this case, a screw hole may be provided in place of the hexagonal hole, a tool for removal may be screwed in, and then the tool may be pulled out to remove the nozzle.

1. Spindle (drill body)
2 ... Coolant supply passage 4 ... Chip discharge groove 6 ... Chip 8 ... Coolant ejection hole 9 ... Communication passage 10 ... Jet injection nozzle 11 ... Hexagon hole 12 ... Tapered hole 13 ... Orifice

Claims (2)

In a drill or gun drill in which a tip surface of a drill body is formed flat and a tip as a cutting blade is attached to the drill body facing the flat surface,
The drill body is provided with a discharge groove twisted around the periphery of the drill body, and the twist direction of the coolant supply passage formed inside the drill body and the inclination angle of the discharge groove are formed with the same twist angle and meshed. And
A coolant ejection hole is provided on a chip discharge groove surface. It is set so that it is jetted directly toward the contact portion between the cutting edge of the insert and the work material ,
Coolant ejected at a high pressure of 7 MPa or more and 30 MPa or less is directly ejected to the contact portion between the cutting edge surface of the tip and the work material, and the chips shaved from the work material are cut by the coolant together with the coolant. A drill or a gun drill, which flows into a discharge groove and processes the workpiece while being discharged from the drill through the discharge groove. In the coolant ejection hole, a jet ejection nozzle that strengthens the ejection force is detachably attached,
2. The drill according to claim 1, wherein the jet injection nozzle includes a hole for ejecting a coolant on a front end surface side, a tapered hole for narrowing the coolant on a rear end surface side, and an orifice connecting the hole and the tapered hole. 3. Or gun drill.

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