JP4526048B2 - Threading tool - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a drilled tap in which a drill part is provided at the tip and a tap part is provided in connection with the drill part in order to perform under-thread drilling and tapping in one step. The present invention relates to a threading tool using a raised tap that forms a female thread by plastic working.
[0002]
[Prior art]
There are casting, burring, etc. in the preparation of the pilot hole, which is a pre-process of female thread processing, but the most common is processing by a drill. Normally, pilot holes and screws are machined in separate processes. However, since multiple tools, holders, and holder storage parts are required, and it takes time to change the tool, a drill is provided at the tip of the tap and integrated. In recent years, the use of taps with drills that allow the tool to be machined with a single tool has increased. What is shown in FIG. 5 is a tap 30 with a drill in which a hand tap and a pilot hole drill are integrated. At the tip of a hand tap 34 comprising a handle portion 31 and a screw portion 33 having a cutting edge 32 on the outer periphery. The drill part 35 is connected via a small diameter connecting part 36. Further, what is shown in FIG. 6 is a tap 40 with a drill in which a spiral tap and a drill for drilling a pilot hole are integrated. From the screw part 43 having the handle 31 and the cutting edge 42 as in FIG. A drill portion 35 is connected to a tip end portion of the spiral tap 41 via a connection portion 36. A tap with a drill is also called a drill tap.
[0003]
By using such drill taps 30 and 40, the diameter of the prepared hole is processed by the drill portion 35, and then the female threads are processed by the cutting edges 32 and 42 of the taps 33 and 43 that are connected to each other. By pulling out the tap with a drill from the workpiece while reversing, the pilot hole machining and female screw machining are performed with a single tool. Further, in the screw processing by such a cutting tap, the diameter of the prepared hole processed by the drill portion 35 is processed, so that the screw inner diameter is the same and does not change before and after the screw processing. Therefore, even if it reverses after screw processing with a tap with a drill and a tap part is returned, a drill outer peripheral part does not interfere with a screw thread. Therefore, since the drill part and the tap part function as an independent tool without interfering with each other during use, the same shape specifications as the drill and the tap alone can be applied to each part. In other words, the cutting tap can be a tap with a drill simply by adding a drill portion to the tip of the tap.
[0004]
On the other hand, in order to eliminate cutting waste during screw processing or to enhance screw strength, a raised tap that forms a screw by plastic flow of a work material is used regardless of the cutting edge. However, when machining internal threads with a cutting tap, a drill with the same diameter as the internal diameter of the pilot hole internal thread is used, whereas with a build-up tap, the internal thread is formed by the plastic flow of the work material, so it is processed with a drill. A high precision hole diameter is required. In addition, the diameter of the pilot hole drill is set to a diameter close to the effective diameter of the screw. Furthermore, since the workpiece material forms the inner diameter of the female thread by plastic flow after the female thread is formed, the inner diameter of the thread is reduced because it is formed from the drill diameter for drilling the pilot hole. Sometimes the drill periphery interferes with the threads formed by plastic flow. For this reason, it cannot be set as a tap with a drill only by providing a drill part in the front-end | tip of a raising tap. Therefore, it is only necessary to provide a screw groove on the outer periphery of the drill so as not to interfere with the screw thread formed by plastic flow so that the outer periphery of the drill and the screw thread do not interfere when the tapped screw is reversed and returned. .
[0005]
[Problems to be solved by the invention]
However, simply providing a screw groove on the outer periphery of the drill will not ensure the drilling accuracy, which will adversely affect the screw processing accuracy, and the surface of the screw when returning will be easily scratched. There was a problem that accuracy could not be obtained. In view of the above problems, the object of the present invention is a combination of a drill and a rising tap that can obtain a clean and stable plastic working screw equivalent to that of a threaded tap alone even in the process of screw formation unique to the rising tap. It is to provide a tapping tool.
[0006]
[Means for Solving the Problems]
In the present invention, a drill portion having two or more cutting edges, a corner portion, and a torsion groove at one end, a tap portion that is connected to the drill portion via a connection portion, and processes a screw, and the tap portion, In a threading tool having an articulated handle part, the tap part is a raised tap that forms a female thread by plastic working, and the drill part has a diameter capable of machining a pilot hole suitable for plastic working of the female thread of the tap part. A tip having a tip is provided, and the outer periphery of the drill part has a width of 0.9 to 2.2 with a ratio of a thread groove not to interfere with a screw thread plastically processed by the tap part and a torsion groove width. And a margin so that the total width of the margins that are part of the lands is 30% or more of the entire circumference (each margin width is preferably the same width), and a cutting edge formed by a thread groove One corner is missing There drill portion is supported at margin, it has solved the above problems by having to allow stable under drilling.
[0007]
If a thread groove is provided in the outer peripheral portion of the drill, one corner portion of the drill cutting edge is cut off, and the prepared hole machining becomes unbalanced cutting and the prepared hole diameter becomes unstable. This slight change in the diameter of the prepared hole greatly affects the bulging state of the screw formed by plastic flow. In the present invention, a land having a ratio of 0.9 to 2.2 with respect to the width of the twisted groove and a total width of the land margin is 30% or more of the entire outer periphery (each margin width is preferably the same width). ) Is provided so that the drill can be supported by the margin even if one of the corners of the cutting edge due to the thread groove is missing, improving the guidance of the outer periphery, and unbalanced cutting resistance. Even if it becomes, it becomes possible to perform stable pilot hole processing, and it is possible to obtain a pilot hole with high accuracy.
[0008]
If the ratio of the torsional groove width to the land width is less than 0.9, the torsional groove width becomes small, and it is difficult to discharge the cutting waste when preparing the pilot hole. Not stable. Therefore, the ratio of the torsion groove width to the land width is set to 0.9 to 2.2. If the total margin width is less than 30% of the entire outer periphery, the drill cutting edge corners will be missing due to the thread groove, and the cutting resistance will become unbalanced and the drilled hole will expand and become distorted and unstable. The total width of the margin portion was set to be 30% or more of the entire outer circumference so that a stable pilot hole was obtained by improving the guideability. In general, the land of the drill is composed of a margin and a second surface. However, if the margin is set to 100% without providing the second surface, the second step can be omitted and provided at low cost.
[0009]
The thread groove that is made not to interfere with the thread that has been plastically processed by the tap part provided on the outer periphery of the drill part is a thread groove in which the phase of the pitch coincides with that of the raised tap, and its flank surface when the tap is reversed. Is formed by tapping so that it does not come into contact with the flank surface of the screw. However, if the effective diameter and the trough diameter are too small, the outer periphery of the drill may be chipped or a margin cannot be secured. On the other hand, if it is too large, it can easily come into contact with the formed flank surface, and there is a possibility that the outer periphery of the screw or drill formed by cutting chips or plastic working chips being damaged.
[0010]
Therefore, in claim 2, the thread pitch is set to the same pitch of the thread of the tap part, and the effective diameter and the valley diameter are 0.02P to 0 respectively from the effective diameter and the valley diameter of the complete thread part of the tap part. ..20P (P = Pitch mm) small.
[0011]
Although there is a slight difference depending on the plastic fluidity of the material, the height of the thread is uniquely determined by the diameter of the pilot hole, so the height of the thread and the inner diameter of the female thread are determined. Therefore, a stable tap hole machining is required for the raised tap. Therefore, the outer periphery guideability is improved by taking a margin larger than that of a general drill, but the guideability is further improved by setting the back taper in the drill portion to 0 to 0.015 mm in the torsion groove length direction of the drill portion. The stability of the pilot hole diameter is improved. Since the drill to prevent rubbing welding by the machined surface of the hole for entering the drill itself into the hole formed by processing, generally narrow margin, to more than 0.04mm per backed Kutepa to 100mm in further. Since in the present invention to form a screw groove in the drill outer periphery, small amount of contact of the processing surface and the drill outer circumference, because good penetration of cutting oil, it is possible to improve the guiding of the outer periphery to eliminate the margin is wide back taper .
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 and 2. 1A and 1B are explanatory views showing an embodiment of the threading tool of the present invention, in which FIG. 1A is a side view, FIG. 1B is a front view seen from the tip side, and FIG. 1C is an AA arrow in FIG. FIG. 2 is a partially enlarged explanatory view in the vicinity of a connecting portion where the drill portion and the tap portion of FIG. 1 are connected. In the example of FIG. 1, a twisted blade drill (twist drill) 2 having a pair of twisted grooves is disposed at the tip of the rising tap. As shown in FIG. 1, the threading tool of the present invention comprises a raised tap portion 1, a drill portion 2, and a handle portion (shank portion) 3. As shown in FIG. 2, a biting portion 5 is formed at the tip of the raised tap portion 1, and a connection portion (neck) 7 is formed so as to be connected to the rear end 6 of the drill portion. The tap portion 1 is the same as a conventional raised tap, and as shown in FIG. 1C, there are four convex radial portions 1a for forming screw threads and four relief portions 1b having a smaller effective diameter than the radial. It is arranged equally. In addition, in FIG.1 (c), the cross section of the escape part is simplified.
[0013]
The outer diameter (diameter) 2d of the drill portion is dimensioned so that the screw catch rate is 80 to 95% because it is processed. The minimum diameter of the pilot hole is when the caught rate of the processed screw is 100%, and the catch rate of the female screw decreases as the diameter of the prepared hole increases. The drill diameter is determined from the range of the required catch rate. Generally, the size is larger than the effective screw diameter. The chamfered portion 5 of the raised tap is formed with threads 5a and 5b so that the effective diameter is sequentially reduced from the complete threaded portion 1a... 1a of the tap portion 1, and the chamfered tip outer diameter 5d is outside the drill portion 2. The diameter is smaller than 2d. A screw groove 21 is provided on the outer periphery 2a of the drill portion 2, and the pitch of the screw groove is the same as that of the screw of the tap portion 1 , and the effective diameter of the screw in the screw groove and the diameter of the valley 21d are set in the tap portion. The effective diameter of the complete thread portion and the diameter 1c of the valley are each smaller by 0.02P to 0.20P. A thread groove on the outer periphery of the drill portion is formed continuously from the biting portion 5, but the effective diameter of the screw from the biting portion to the drill portion is continuously increased gradually at the connection portion 7. The effective diameter of the screw means a diameter of the cylinder such that the width of the thread portion is equal to the width of the thread groove portion when the thread is cut by a cylindrical surface having the axis of the screw as an axis.
[0014]
The drill portion has a pair of twist grooves 8, a chisel 9, a cutting edge 10, a corner portion 11, a land 12, a margin 13 and the like in the same manner as a general twist drill. There is no surface. That is, the land is used as a margin as it is. Further, a back taper of preferably 0 to 0.015 mm is provided in the direction of the torsional groove length L. A similar effect can be expected with a double margin drill having two margins in one land instead of increasing the margin. In addition, a margin width may be ensured in a comprehensive manner even with three or more twisted grooves. That is, the gist of the present application is that there is no deterioration of the machined surface due to rubbing with the work material by having a thread groove on the outer periphery, and even if the cutting edge corner is unbalanced by securing a margin width, etc. The guide width is large and is supported by the pilot hole.
[0015]
Next, a machining method using such a screw machining tool will be described. FIG. 3 is a partially enlarged cross-sectional view showing a state in which the internal thread of the female thread after the pilot hole processing is inserted into the workpiece and plastic machining of the internal thread is performed, and FIG. It is a partial expanded sectional view which shows the state which pulls out a tool from a workpiece | work. In FIG. 3, the drill portion 2 is rotated into the work 31 to machine the work hole 32. The inner diameter 32d of the pilot hole 32 is a drill outer diameter 2d. As the drill part 2 and the tap part 1 of the thread machining tool enter, the work screw 31 has an internal thread 33 in the order of 5c, 5b, 5a, beginning to bite into the pilot hole 32 between the biting parts 5d and 5c of the tap part 1. The plastic working is completed, and the plastic working is completed at the complete screw thread portions 1a. The internal thread diameter 33d of the workpiece is machined slightly larger than the diameter 1c of the valley of the complete thread portion of the tap portion 1 .
[0016]
After completion of the internal thread machining of a predetermined length, as shown in FIG. 4, the internal thread 33 has the same pitch as that of the thread 1a, 1a, 5a to 5d of the tap portion. This is the same as the pitch of the thread groove 21. Furthermore, the internal diameter 33d of the internal thread is made larger than the diameter 21d of the valley of the thread groove. Therefore, the threading tool can be easily removed from the work 31 without interference between the female screw 33 and the drill portion 2, and the drill and the tap can be integrated with each other regardless of the rising tap. Needless to say, the rotation and feed are controlled to values suitable for screw machining after the start of biting and when the tool is removed from the workpiece.
[0017]
【The invention's effect】
As described above, in the threading tool of the present invention, the tap portion is a raised tap, and the drill portion has a ratio of a thread groove to a torsion groove width of 0.9 to 2.2 on the outer periphery of the drill portion. Even if one corner portion of the cutting edge by the thread groove is missing, by providing a land having a width of 30 mm and a margin in which the total width of the land margins is 30% or more of the entire outer circumference. the drill unit is supported by a margin, the lower drilling a stable, than as possible out to obtain a prepared hole of high precision, resulting plastic working screws clean stable threading when the same with tap alone thread forming A threading tool that combines a drill and a raised tap is provided. Furthermore, although it is a raised tap, it can be processed from pilot hole machining to screw machining with one tool, so that the machining time can be shortened and the cost can be reduced. For example, when the conventional pilot hole and the rising tap are separately used, the machining time which takes about 35 seconds is significantly reduced to 15 seconds according to the screw machining tool of the present invention.
[0018]
In addition, the effective diameter and valley diameter are 0.02P to 0.20P smaller than the effective diameter and valley diameter of the complete thread portion of the tap part, respectively, to minimize the interference between the plastically processed screw and the drill part. As a result, a more accurate plastic screw can be machined with a single tool. Furthermore, by setting the back taper in the torsional groove length direction of the drill portion to 0 to 0.015 mm, more stable pilot hole processing can be achieved, and more accurate screw processing is possible.
[Brief description of the drawings]
FIG. 1A is a side view showing an embodiment of a threading tool of the present invention, FIG. 1B is a front view seen from the front end side, and FIG. 1C is a cross-sectional view taken along line AA in FIG. It is.
FIG. 2 is a partially enlarged explanatory view in the vicinity of a connecting portion where the drill portion and the tap portion of FIG. 1 are connected to each other, showing an embodiment of the threading tool of the present invention.
FIG. 3 is a partially enlarged cross-sectional view showing a state during plastic working of a female screw after a threading tool of the present invention has entered a work and drilled a pilot hole.
FIG. 4 is a partially enlarged cross-sectional view showing a state in which the threading tool of the present invention is removed from the workpiece after plastic working of the female screw to the workpiece.
FIG. 5 is a side view of a tap with a drill in which a conventional hand tap and a pilot hole drill are integrated.
FIG. 6 is a side view of a tap with a drill in which a conventional spiral tap and a drill for preparing a pilot hole are integrated.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tap part 1c Tap part diameter of the thread part of a complete thread part 2 Drill part 2a Drill part outer periphery 2d Diameter (outer diameter of a drill part)
3 Handle 7 Connection (Neck)
8 Torsion groove 12 Land 13 Margin 21 Thread groove 21d Thread groove trough diameter L Drill groove torsion groove length

Claims (3)

A drill portion having two or more cutting edges, a corner portion, and a torsional groove at one end; a tap portion that is connected to the drill portion via a connection portion so as to process a screw; and a handle portion that is connected to the tap portion. The tap portion is a raised tap that forms a female screw by plastic working, and the drill portion has a tip that has a diameter capable of machining a pilot hole suitable for plastic working of the female screw of the tap portion. A screw groove which is plastically processed by the tap portion on the outer periphery of the drill portion so as not to interfere with the screw, and a width of the torsion groove width is 0.9 to 2.2. And a margin in which the total width of a margin that is a part of the land is 30% or more of the entire outer periphery, and one corner portion of the cutting edge by the thread groove is provided. Even if it is missing, Screw machining tool, characterized in that supporting the drill part in emissions, which is to be stable under drilling. The thread groove is the same as the thread pitch of the tap part, and the effective diameter and valley diameter are 0.02P to 0.20P (P = pitch), respectively, from the effective diameter and valley diameter of the complete thread part of the tap part. 2. The threading tool according to claim 1, wherein the threading tool is made smaller. The threading tool according to claim 1 or 2, wherein a back taper in a length direction of the twisted groove of the drill portion is set to 0 to 0.015 mm.

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