JP2010082777A - Drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drill in which burrs can be prevented from being generated on an outlet peripheral edge part of a through-hole which is formed in drilling and from which a drill blade comes out. <P>SOLUTION: The drill 1 includes a shank, a drill body 10 continuing to the shank, a preceding blade 14 formed on a tip end of the drill body 10, and a finishing blade 17 formed in a shank side of the preceding blade 14 in the drill body 10 and in an outer peripheral side of the preceding blade 14. A workpiece is cut by the preceding blade 14 and the finishing blade 17. In cutting the workpiece, feed speed of the drill body 10 when the preceding blade 14 penetrates through the workpiece is set faster than that of the drill body 10 when the finishing blade 17 penetrates through the workpiece and set to the speed to arrow chipping to be generated on the workpiece. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a drill that suppresses burrs generated during drilling.

When a through-hole is opened in a workpiece by a drill (during drilling), burrs are likely to be generated at the peripheral edge of the drill blade exit, and problems such as product troubles may occur due to such burrs falling off.
Techniques for solving the above problems are known. For example, it is disclosed in Patent Document 1.

  The technique described in Patent Document 1 has a conical portion and a rod body portion following the conical portion, a plurality of leading blades in the conical portion, and a lower end of the leading blade, the rod body portion, A finishing blade that is inclined with respect to the shaft center is formed, and a drill that forms a substantially L-shaped step between the preceding blade and the finishing blade by cutting out the vicinity of the continuous portion is used. It is intended to suppress burrs by completely scraping the periphery.

At the time of drilling, burrs may be generated at the peripheral edge of the drill blade exit of the formed through hole. The method of generating this burrs can be roughly classified into two types.
First, as shown in FIG. 5 (a), when cutting a workpiece with the drill blade 100, especially when the feed rate of the drill is set to be relatively slow, the chips are caused by the feed force of the drill. It is pushed out of the through hole and remains in a state where it is not separated from the workpiece, and a burr 101 is generated at the peripheral edge of the drill blade outlet. At this time, the burr 101 is relatively large.
Second, as shown in FIG. 5B, when the drill blade 100 penetrates the workpiece, the workpiece 102 at the drill blade outlet peripheral portion remains in a state of being plastically deformed and extruded, A burr 103 is generated at the periphery of the drill blade outlet of the formed through hole. At this time, the burr 103 is relatively small.

  Therefore, in order to suppress the occurrence of burrs at the peripheral edge of the drill blade exit of the through-hole formed during drilling, it is necessary to suppress two types of burrs having different generation methods.

Generally, the finishing blade is used to smoothly finish the hole wall surface cut by the leading edge, and the cutting action is secondary, and the machining allowance is set to be much less than the machining allowance of the leading edge. . For this reason, at the time of drilling, the thickness of the burr exceeds the machining allowance of the finishing blade, and it may be difficult to scrape the burr with the finishing blade. Such a situation is likely to occur particularly when a relatively large burr is generated as described above.
Japanese Utility Model Publication No. 57-75916

  In view of the above situation, the present invention provides a drill that can suppress the occurrence of burrs in the peripheral edge of the drill blade outlet of a formed through hole during drilling.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  The drill according to claim 1, comprising a shank and a drill body connected to the shank, wherein a leading blade is formed at a tip portion of the drill body, the shank side with respect to the leading blade in the drill body, and A finishing blade is formed on an outer peripheral side of the preceding blade, and the drill is configured to cut a workpiece with the leading blade and the finishing blade, and the leading blade is cut when the workpiece is cut. The feed speed of the drill body when penetrating the workpiece is faster than the feed speed of the drill body when the finishing blade penetrates the workpiece, and an edge defect occurs in the workpiece. The speed is set to about.

  3. The drill according to claim 2, wherein the finishing blade is inclined so as to be directed toward a feed direction of the drill as it goes radially outward of the drill body, and an outer peripheral surface of the drill body. A second blade that is connected to the rear side in the rotation direction of the first blade and is inclined so as to go to the feed direction side of the drill body as it goes from the front side to the rear side in the rotation direction of the drill body. .

  The present invention has an effect that it is possible to suppress the generation of burrs at the peripheral edge of the drill blade outlet during drilling.

Below, the drill 1 which is one Embodiment of the drill which concerns on this invention is demonstrated.
1 to 4, the direction indicated by the arrow A is the rotation direction of the drill body 10, and the direction indicated by the arrow B is the feed direction of the drill body 10.

As shown in FIGS. 1 and 2, the drill 1 is a cutting tool for making a hole in a workpiece.
The drill 1 is a stepped drill including a shank (not shown) made of tool steel and the like, and a drill body 10 supported by the shank and made of a super high alloy.

  The drill body 10 is formed with a drill blade (a leading blade 14 and a finishing blade 17 which will be described later), which is a main part of the drill 1 that performs a function of cutting a workpiece. It is connected to the shank, and its tip is formed in a substantially rod shape protruding in the axial direction of the shank, and the drill blade (the leading blade 14 and the finishing blade 17) is formed from the middle part of the drill body 10 to the tip side. Has been.

The drill body 10 is formed on the outer peripheral surface of a protruding portion that protrudes radially outward from the axial center portion of the drill body 10, and a pair of first lands 11 extending in the axial direction of the drill body 10 and the first lands 11 are formed. Is formed on the outer peripheral surface of the projecting portion which is disposed at a phase shifted by approximately 90 ° to the rear side in the rotation direction of the drill body 10 with respect to the projecting portion, and projects radially outward from the axial center portion of the drill body 10. A pair of second lands 12 extending in the axial direction of the body 10.
The pair of first lands 11 are disposed at positions that are substantially 180 degrees out of phase with each other, and the pair of second lands 12 are also disposed at positions that are approximately 180 degrees out of phase with each other.

  Grooves 13a and 13b are alternately formed between the first land 11 and the second land 12, respectively. The grooves 13a and 13b extend in the axial direction of the drill body 10 from the distal end portion to the proximal end portion of the drill body 10, and when the drill 1 makes a through hole in the workpiece (drilling), the coolant is in the groove 13a. Then, it is supplied to the finishing blade 17 and the cutting waste (chip) of the workpiece is discharged outside the through hole through the groove 13b.

  The front side of the drill body 10 in the second land 12 in the rotational direction is concentric with the axis of the drill body 10, and the rear side in the rotational direction of the drill body 10 is in a margin 12 a that substantially contacts the wall surface of the hole formed during drilling. Are respectively formed on relief surfaces 12b provided in a state where a part of the outer periphery of the margin 12a is escaped.

  The distal end portion of the drill body 10 is formed in a substantially conical shape whose diameter decreases from the distal end portion of the first land 11 and the second land 12 toward the distal end side of the drill body 10. Pointed to the side. A pair of leading blades 14 are formed at the distal end portion of the drill body 10 from the distal end portion of the first land 11 toward the distal end of the drill body 10. On the rear side in the rotational direction of the leading blade 14 (drill body 10), a tip flank 15 that is inclined toward the base end side of the drill body 10 as it goes radially outward of the drill body 10 is formed.

As shown in FIGS. 2 and 3A, a step portion (inclined surface 16) is formed in the middle portion of the drill body 10 where the second land 12 is formed. Thus, the diameter on the base end side of the drill body 10 in the portion where the second land 12 is formed is slightly larger than the diameter on the tip end side.
The inclined surface 16 is inclined toward the feed direction of the drill body 10 as it goes outward in the radial direction of the drill body 10.

The inclined surface 16 is connected to the first side which is a side located on the front side in the rotational direction of the drill body 10 and the first side, and is located on the outer peripheral surface of the drill body 10 (the second land 12 is formed). And a second side which is a side located at the boundary between the surface and the stepped portion.
The first side is formed on the first blade 17a, and the first side (first blade 17a) is inclined to the feed direction side as it goes outward in the radial direction of the drill body 10.
The second side is formed on the second blade 17b, and the second side (second blade 17b) extends from the first blade 17a to the rear side in the rotation direction of the first blade 17a. It is formed along the outer peripheral surface. Further, the second side (second blade 17b) is inclined so as to go to the feed direction side of the drill body 10 as it goes from the front side to the rear side in the rotation direction of the drill body 10 (see FIG. 1).
The finishing blade 17 is constituted by the first blade 17a and the second blade 17b formed in this way.

Explaining the positional relationship between the leading blade 14 and the finishing blade 17, the leading blade 14 is formed at the tip of the drill body 10, and the finishing blade 17 is formed at the step (inclined surface 16) in the middle of the drill body 10. Is done.
That is, the finishing blade 17 is formed behind the leading blade 14 (on the base end side of the drill body 10) and on the outer peripheral side (outside in the radial direction of the drill body 10) than the leading blade 14, and the drill body 10 is formed in a stepped shape between a portion where the leading blade 14 is formed and a portion where the finishing blade 17 is formed.
Accordingly, the outermost end of the finishing blade 17 slightly protrudes outward in the radial direction of the drill body 10 from the outermost end of the leading blade 14, and the allowance for the finishing blade 17 is set by the amount of the protruding portion. 14 and finishing blade 17 divide the machining allowance.

  In addition, although this embodiment formed the pair of finishing blades 17, the present invention is not limited to this, and a plurality of pairs may be formed.

  The drill 1 includes a motor or the like, and includes a first drive device (not shown) that rotates the drill body 10 around an axis, a motor, a pneumatic cylinder, a hydraulic cylinder, and the like, and moves the drill body 10 in the feed direction. Drill drive comprising: a second drive device (not shown); and a control device (not shown) for controlling the operation and stop of each device by transmitting a signal to each of the first drive device and the second drive device Driven by the device.

As shown in FIG. 3 (a), when a drill 1 is used to open a through-hole from the surface of the workpiece to the back surface, first, the tip of the drill body 10 (leading blade 14) is brought into contact with the surface of the workpiece. Let The control device transmits a signal to the first drive device and the second drive device, thereby moving the drill body 10 at a predetermined feed speed while rotating the drill body 10 at a predetermined rotation speed. As a result, the workpiece is scraped off by the leading edge 14 to form a pilot hole, and then the prepared hole wall surface is precisely scraped off by the finishing blade 17.
Then, when the leading blade 14 starts to penetrate the workpiece, the control device transmits a signal to the second driving device to set the feed speed of the drill body 10 to the preceding feed speed. As a result, the leading edge 14 penetrates the workpiece at the preceding feeding speed.
Then, as shown in FIG. 3B, the control device sends a signal to the second driving device after the leading blade 14 has penetrated the workpiece and before the finishing blade 17 starts to penetrate the workpiece. Is transmitted, the feed speed of the drill body 10 is decelerated from the preceding feed speed. The workpiece is cut while the feed rate of the drill body 10 is reduced, and the finishing blade 17 penetrates the workpiece as shown in FIG. That is, the feed speed of the drill body 10 when the leading blade 14 penetrates the workpiece (the preceding feed speed) is faster than the feed speed of the drill body 10 when the finishing blade 17 penetrates the workpiece. Thus, the drill 1 is rotationally driven.

The preceding feed speed is generally high enough to cause chipping of the edge, that is, high enough to sever the chips generated when forming the through hole in the work piece from the work piece. It is determined appropriately in consideration of the material quality of the object.
In addition, when the feed speed of the drill body 10 is decelerated from the preceding feed speed, the control device decelerates based on the viewpoint of reducing the resistance generated in the feed direction of the drill body 10, It decelerates at a degree that does not occur (for example, 1-2% of the diameter).

  With this configuration, when the leading blade 14 passes through the workpiece (penetrates), the leading blade 14 that moves at the preceding feed speed can cause the chipping, that is, the chips can be divided. This prevents the chips from being pushed out of the through hole by the feed force of the drill 1 without being cut off from the workpiece, and remaining as burrs at the outlet peripheral edge of the drill blade. Therefore, generation | occurrence | production of a burr | flash can be suppressed in the exit peripheral part of the said drill blade, and especially a comparatively big burr | flash can be suppressed.

  Further, as shown in FIGS. 3 (b) and 3 (c), the machining allowance of the finishing blade 17 is set behind the leading edge 14 and on the outer peripheral side, so that the leading edge 14 passes through the workpiece. Further, the burr 2 a generated by plastic deformation of the workpiece at the outlet peripheral edge of the leading blade 14 can be cut with the finishing blade 17. Therefore, generation | occurrence | production of a burr | flash can be suppressed in the exit peripheral part of the said drill blade, and especially a comparatively small burr | flash can be suppressed.

  Further, the finishing blade 17 is inclined in the feed direction side toward the radially outer side of the drill body 10, and the first blade 17 a on the outer peripheral surface of the drill body 10 in the rotation direction. Since the second blade 17b is connected to the rear side and is inclined so as to go to the feed direction side of the drill body 10 as it goes from the front side to the rear side in the rotational direction of the drill body 10, the machining allowance of the finishing blade 17 is increased. The chips 2b are discharged from the outer peripheral side to the inner side (toward the inner side in the radial direction of the drill body 10). Therefore, it is possible to suppress plastic deformation of the workpiece at the exit peripheral edge of the finishing blade 17 when the finishing blade 17 passes through the workpiece, and it is possible to suppress burrs because clean cutting can be performed.

  Moreover, it is not necessary to provide the process of removing the burr | flash generate | occur | produced in the exit peripheral part of the said drill blade separately from the drilling process by the drill 1, and can drill efficiently.

Moreover, as shown to Fig.4 (a), it is preferable that the magnitude | size of the clearance angle (2nd angle | corner) (alpha) of the flank 12b shall be 10 degrees-15 degrees.
Further, as shown in FIG. 4 (b), the second blade 17b of the finishing blade 17 is inclined to the feed direction side of the drill body 10 while extending to the rear side in the rotation direction of the drill body 10, and this inclination is the drill body. It is preferable to incline by 5 ° to 35 ° with respect to the plane perpendicular to the 10 feed directions. Note that an angle formed by the inclination of the finishing blade 17 and a surface perpendicular to the feed direction of the drill body 10 is defined as a negative angle β. In particular, β = 5 ° is advantageous in that the chip can be shortened and the rigidity of the finishing blade 17 is increased.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram showing a first example of an embodiment of a drill according to the present invention. The schematic block diagram when the drill body shown in FIG. 1 is seen from the direction of arrow C. (A) Cross-sectional view showing when the drill is cutting the workpiece, (b) Cross-sectional view showing when the leading blade has penetrated the workpiece, (c) Finishing blade has penetrated the workpiece Sectional drawing which shows time. (A) The figure which shows clearance angle (alpha), (b) The figure which shows negative angle (beta). (A) The figure which shows when a comparatively big burr | flash generate | occur | produces at the time of a drill process, (b) Similarly the figure which shows when a comparatively small burr | flash generate | occur | produces.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Drill 10 Drill body 14 Leading blade 16 Inclined surface 17 Finishing blade 17a First blade 17b Second blade

Claims (2)

A shank and a drill body connected to the shank;
A leading edge is formed at the tip of the drill body, a finishing blade is formed on the shank side of the leading edge in the drill body, and an outer peripheral side of the leading edge,
A drill that cuts a workpiece with the preceding blade and the finishing blade,
The feed rate of the drill body when the leading blade penetrates the workpiece when cutting the workpiece is the feed rate of the drill body when the finishing blade penetrates the workpiece. A drill that is set to a speed that is faster than the workpiece and that causes chipping of the workpiece. The finishing blade is
The first blade that is inclined so as to go to the feed direction side of the drill as it goes radially outward of the drill body, and continues to the rear side in the rotation direction of the first blade on the outer peripheral surface of the drill body, A second blade that is inclined so as to go to the feed direction side of the drill body as it goes from the front side to the rear side in the rotational direction of the drill body;
The drill according to claim 1.

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