JPH0611923U - Perforated threading coupling tool for through holes - Google Patents

Abstract

(57) [Abstract] [Purpose] A multi-threaded thread cutting blade with a lead-free multi-threaded thread cutting blade and a multi-threaded thread cutting blade, which is used to cut a female thread into a pilot hole formed by the multi-thread thread cutting blade. Reduces interference cutting during female thread processing. [Configuration] Outer diameter d ₂ of multi-threaded thread cutting blade 28 without lead
Was 90% or less of the outer diameter d ₁ of the outer peripheral blade 24 of the punching blade 20.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 TECHNICAL FIELD The present invention relates to an improvement of a through hole threading coupling tool for through holes, which is integrally provided with a drilling blade for processing a prepared hole in a workpiece and a screw cutting blade for processing a female screw in the prepared hole.

[0002]

[Prior art]

 There is a thread milling machine as a tool for cutting an internal thread. This is equipped with a thread cutting blade having a shape corresponding to the thread groove of the female screw to be formed, and is attached to, for example, an NC milling machine or a machining center to be driven to rotate around the axis and inside the prepared hole of the workpiece. By making relative movement in the circumferential direction and axial direction of the pilot hole while making a cut in the circumferential surface, a female screw is cut on the inner circumferential surface of the pilot hole. The equipped multi-threaded thread milling machine is widely used. When cutting an internal thread using such a thread milling machine, it is necessary to pre-drill a prepared hole of approximately the same size as the internal diameter of the internal thread to be formed as a pre-step. Due to the equipment and time required for tool change, recently, a joining tool has been proposed in which a drilling tool is integrally provided at the tip of a thread milling cutter. The tools described in Japanese Patent Laid-Open No. 63-200916 and Japanese Patent Laid-Open No. 3-184722 are one example, and the outer diameter of the thread cutting blade for processing a female screw is a drilling blade for machining a pilot hole. It is the same as the outer diameter of the hole, or slightly smaller than the outer diameter of the drilling blade to prevent it from interfering with the inner surface of the prepared hole during drilling.

[0003]

[Problems to be solved by the device]

 By the way, when cutting a female thread with a lead with a threadless blade without a lead, as in the above-mentioned thread milling cutter, interference cutting in which the thread groove shape of the female thread is larger than the shape of the thread cutting blade is unavoidable. It becomes remarkable when processing a large internal thread and when the milling diameter is close to the root diameter of the internal thread to be processed. In the conventional drilling thread cutting coupling tool described above, since the outer diameter of the thread cutting blade is substantially equal to the outer diameter (prepared hole diameter) of the drilling blade, the inner diameter of the female screw is generally about 85 to 95% of the root diameter, and the inner diameter is Since it is almost equal to the hole diameter, the outer diameter of the thread cutting blade with respect to the root diameter is about 85 to 95%, and the above interference cutting becomes a problem. As a countermeasure, the width of the thread cutting blade has been narrowed in consideration of the amount of cutting due to interference, but there is a limit in strength to such blade shape modification.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a drilling threaded coupling tool for a through hole having less interference cutting.

[0005]

[Means for Solving the Problems]

 In order to achieve such an object, the present invention has a drilling blade for cutting a prepared hole at the front end in the axial direction, and a leadless multi-mounting machine for cutting a female screw into a prepared hole formed by the drilling blade. A screw cutting blade is integrally provided on the rear side in the axial direction with respect to the drilling blade and is axially moved relative to the work piece while being driven to rotate about the axis, thereby processing the prepared hole with the drilling blade. After that, the internal thread of the pilot hole is machined by the multi-threaded thread cutting blade described above by being driven to rotate about the axis and being relatively moved in the pilot hole in the axial and circumferential directions. In the hole drilling threaded connection tool for holes, the outer diameter of the multi-threaded thread cutting blade is 90% or less of the outer diameter of the hole drilling blade.

[0006]

[Effect of action and device]

 In such a through hole drilling threaded connecting tool, the outer diameter of the multi-threaded screw cutting blade is 90% or less of the outer diameter of the drilling blade, so that the outer diameter of the multi-threaded thread cutting blade with respect to the root diameter of the female screw to be machined. When the internal diameter of the multithreaded thread cutting blade is less than 85% of the internal thread root diameter, and the internal diameter is about 85% of the root diameter, for example, when machining female threads whose inner diameter is about 95% of the root diameter. In the case of cutting the female screw, the outer diameter of the multi-threaded thread cutting blade is about 76% or less of the female thread root diameter. As a result, the amount of interference cutting is reduced, and the amount of edge shape correction that takes into consideration the interference cutting is also within a range that poses no practical problems in terms of strength.

[0007] Specifically, a case of processing a M10 × 1.5 60 ° triangular screw will be described. The allowable range t of the roundness of the valley in the JIS thread form is the dimension from the peak of the peak and the height of the peak. In the case of a 60 ° screw with a pitch of 1.5 mm, the height of the peak is about 1.299 mm, so t≈0.162 mm. In this case, when the outer diameter of the drilling blade is made equal to the inner diameter of the internal thread of 8.5 mm and the outer diameter of the multi-threaded thread cutting blade is 100% of that, that is, 8.5 mm, from the peak of the peak of the roundness of the valley by interference cutting about 0.208mm next when determining the range t _a by calculation, it exceeds the allowable range t ≒ 0.162mm. FIG. 7A shows the cutting state in this case, and the shaded portion is the interference cutting range. On the other hand, when the outer diameter of the multi-threaded thread cutting blade is set to 90% of the outer diameter of the drilling blade (inner diameter of the internal thread), that is, 7.65 mm, the range t _b from the peak of the peak of the roundness of the valley due to interference cutting ≈0.114 mm, which is smaller than the allowable range t≈0.162 mm. FIG. 7B shows the cutting state in this case, and the hatched portion is the interference cutting range. If the outer diameter of the multi-threaded thread cutting blade is 80% of the outer diameter of the hole cutting blade (female thread inner diameter), that is, 6.8 mm, the range from the peak of the peak of the roundness of the valley due to interference cutting is 0.072 mm. If the outer diameter of the multi-thread screw cutting blade is 70% of the outer diameter of the drilling blade (inner diameter of the internal thread), that is, 5.95 mm, the range from the peak of the peak of the roundness of the valley by interference cutting is 0.052 m. m, and when the outer diameter of the multi-thread screw cutting blade is 60% of the outer diameter of the drilling blade (inner diameter of female thread), that is, 5.1 mm, the range from the peak of the peak of the roundness of the valley by interference cutting The circumference is 0.041 mm. In the case of 90%, 0.162-0. 114 = 0.048 mm, but the crest of the thread cutting blade prevents chipping, so in practice at least a 0.02-0.04 mm flat or R part is required, which should be taken into consideration. Then, it becomes a little less than 90%, and it is understood that it is practically necessary to set it to 90% or less.

Here, the smaller the ratio of the outer diameter of the multi-threaded thread cutting blade to the outer diameter of the drilling blade, the smaller the interfering cutting amount, but the flexural rigidity and torsional strength of the tool, the bending strength, and the chips It is desirable to set the outer diameter of the multi-threaded thread cutting blade within the range of about 70% or more of the outer diameter of the punching blade because the dischargeability becomes poor. If it is 70% or less, the interference cutting amount hardly changes even if it is further reduced, and it is necessary to place more importance on the rigidity and strength of the tool.

Further, the maximum diameter is larger than the outer diameter of the boring blade and is relatively driven axially relative to the rear side in the tool axial direction with respect to the multi-threaded thread cutting blade, and is relatively moved in the axial direction. If the first chamfering blade for chamfering is provided on the inlet side of the hole, chamfering can be continuously performed on the inlet side of the pilot hole with a single tool before or after processing the female thread with the multi-threaded cutting blade. This makes it possible to save processing equipment and processing time compared to using a dedicated tool for chamfering.

Further, at least one of the front end and the rear end in the tool axial direction of the multi-thread screw cutting blade has a maximum diameter larger than the outer diameter of the multi-thread screw cutting blade, and the multi-thread screw cutting blade is used to cut an internal thread. In this case, if a second chamfering blade that chamfers the opening of the prepared hole is continuously provided on the top of the multi-threaded thread cutting blade, it becomes possible Chamfering is performed at the same time, which saves processing equipment and processing time compared to the case where a dedicated chamfering tool is used. Further, the chamfering chamfers the incomplete thread of the female screw opening, so that the reduction of the female screw life due to such deformation or damage of the incomplete thread is prevented.

In addition, at least one of a front end and a rear end in the tool axial direction of the multi-threaded thread cutting blade is provided with a cutting edge for removing an incomplete thread having an outer diameter substantially equal to the outer diameter of the multi-threaded thread cutting blade. If it is provided continuously on the top of the thread cutting blade, incomplete threads on the inlet side and the outlet side of the prepared hole will be removed when female threads are machined by the multi-threaded thread cutting blade, so that such incomplete thread deformation will occur. It is possible to prevent the life of the internal thread from being shortened due to damage or damage.

Further, if the length dimension of the multi-threaded thread cutting blade in the tool axial direction is set to be substantially the same as the wall thickness of the workpiece to be machined with an internal thread, the prepared hole for the tool required for internal thread machining Since the number of revolutions is usually 1 to 2 revolutions, the second chamfering blade chamfers both the inlet side and the outlet side of the prepared hole when cutting the female screw, Incomplete threads on both the entry and exit sides of the hole can be eliminated. In other words, when cutting an internal thread with two revolutions, the tool moves in the axial direction by 2 pitches, so if the length of the multi-threaded thread cutting blade is the same as the thickness of the workpiece. It is possible to chamfer each end of the pilot hole by a maximum of about 1 pitch, and when cutting the female screw with one revolution, the tool moves in the axial direction by one pitch. If the length of the multi-threaded thread cutting blade is made shorter than the wall thickness of the work piece by about 1 pitch, chamfering of a maximum of about 1 pitch can be performed on both ends of the prepared hole. The first chamfering edge may be chamfered on the inlet side of the prepared hole, and the second chamfered blade may be chamfered on the outlet side of the prepared hole. It does not matter if the length of the thread cutting blade in the tool axial direction is larger than the wall thickness of the workpiece. If the length dimension of the multi-threaded thread cutting blade in the tool axis direction is larger than the wall thickness of the workpiece, chamfer both ends of the prepared hole with the second chamfering blade described above, or use the To remove incomplete threads on both ends of the hole, for example, shift the tool in the axial direction after machining the internal thread, or move the tool in the axial direction while revolving the tool in the circumferential direction of the prepared hole many times during the internal thread machining. However, it suffices to chamfer both ends of the prepared hole and remove incomplete threads.

Further, when the multi-threaded thread cutting blade and the drilling blade are formed on a common land extending in the tool axial direction, a margin may be provided on the outer peripheral portion of the land of the drilling blade. desirable. That is, since re-grinding of a multi-threaded thread cutting edge is usually performed on the rake face, if the multi-threaded thread cutting edge is formed on the common land with the multi-threaded thread cutting edge, the re-grinding of the multi-threaded thread cutting edge causes The rake face is also ground, and if there is no margin, the outer diameter of the drilling blade and the prepared hole diameter will decrease with grinding.However, if a margin is provided on the outer periphery of the land of the drilling blade. The outer diameter of the drilling blade is kept constant regardless of the re-grinding of the multi-threaded thread cutting blade.

[0014]

【Example】

 An embodiment of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a front view of a through hole threading connection tool (hereinafter simply referred to as a connection tool) 10 according to an embodiment of the present invention as viewed from a direction perpendicular to an axis, and FIG. It is the bottom view which looked at from the front end side. The coupling tool 10 integrally includes a shank 12 that is gripped by an NC milling machine or the like and is driven to rotate about an axis, and a blade portion 14 that cuts a workpiece. The blade portion 14 is formed with a pair of twisted grooves 16 twisted clockwise in this embodiment, that is, in the rotational cutting direction, symmetrically with respect to the axis, and extends in the tool axial direction and twists spirally. Land 18 is provided. The shank 12 is omitted in FIG.

A piercing blade 20 is provided at a front end portion of the land 18 in the tool axial direction. Cutting head 20 is provided with a bottom edge 22 and the peripheral cutting edge (leading edge) 24, (the outer diameter of the cutting head 20) diameter of the outer peripheral edge 24 d ₁ is slightly or the same as the inner diameter of the female thread to be machined smaller In addition, the outer peripheral portion of the perforating blade 20 is provided with a margin 26 of the same size, which is continuous with the outer peripheral blade 24. In addition, a leadless multi-threaded thread cutting blade 28 is provided at an intermediate portion of the land 18 in the tool axial direction, that is, on a rear side of the boring blade 20 in the tool axial direction. The outer diameter dimension d ₂ of the multi-thread screw cutting edge 28 is determined within the range of 70% to 90% of the diameter dimension d ₁ of the outer peripheral edge 24, and in the tool axial direction of the multi-thread thread cutting edge 28. The length dimension L is approximately the same as the thickness of the workpiece 30 (see FIG. 3) on which the internal thread is to be machined. In this embodiment, the length L is shortened by about 0.5 pitch of the thread of the multi-threaded thread cutting blade 28. It is set.

The front end of the multi-thread screw cutting blade 28 in the tool axis direction, that is, the portion between the drilling blade 20 and the multi-thread screw cutting blade 28, has a small diameter as it goes from the drilling blade 20 to the multi-thread screw cutting blade 28. The chamfering blade 32 is formed continuously from the outer peripheral blade 24 of the punching blade 20 to the top of the multi-threaded thread cutting blade 28. At the rear end of the multi-threaded thread cutting blade 28 in the tool axial direction, an incomplete ridge removing cutting edge 34 having an outer diameter substantially equal to the outer diameter dimension d ₂ of the multi-threaded thread cutting blade 28 is provided. It is provided continuously on the top of the. The length dimension of the chamfering blade 32 and the cutting edge 34 for incomplete ridge removal in the tool axial direction is approximately the same as one pitch of the thread of the multi-thread thread cutting blade 28. The chamfering blade 32 corresponds to the second chamfering blade.

The helical groove 16 reaches the front end of the shank 12, and a chamfering blade 36 having a larger diameter toward the shank 12 is provided at the rear of the incomplete ridge removing cutting edge 34. The cutting edge 34 for deletion is provided continuously. The chamfering blade 36 corresponds to the first chamfering blade, and the maximum diameter thereof is the same as the diameter dimension of the shank 12 and larger than the outer diameter dimension d ₁ of the boring blade 20 ₁ .

The connecting tool 10 configured as described above is attached to, for example, an NC milling machine, a machining center or the like and used for cutting an internal thread. FIG. 3 shows a state in which the coupling tool 10 is positioned at a predetermined initial position with respect to the work piece 30 fixed at the work mounting position, and is then indicated by arrows a to f. The female screw is machined on the workpiece 30 by sequentially moving the workpiece 30. FIG. 4 and FIG. 5 are diagrams showing the respective steps at the time of processing the internal thread, and (a) to (f) correspond to the reference numerals of the arrows in FIG. 3, respectively. The internal thread processing step will be specifically described below.

First, in the initial position of FIG. 3, the connecting tool 10 is rotationally driven around the axis and is fed in the axial direction as indicated by the arrow a. FIG. 4 (a) shows this state, in which the prepared hole 40 is cut by the boring blade 20 in the workpiece 30, and the chamfered upper end opening of the prepared hole 40, that is, the opening on the inlet side. A chamfer 42 is provided by the blade 36. The diameter of the prepared hole 40 is the same as or slightly smaller than the inner diameter of the female screw to be machined. After that, the joining tool 10 is lifted up as shown by the arrow b, and the state shown in FIG. At this position, the cutting edge 34 for incomplete thread removal enters into the prepared hole 40 by about 1 pitch of the thread of the multi-thread thread cutting blade 28, and the lower end portion (tip portion) of the multi-thread thread cutting blade 28 is threaded. It is set so as to project downward from the prepared hole 40 by about 0.5 pitch.

Next, the connecting tool 10 is moved in the radial direction of the prepared hole 40 as shown by the arrow c while being rotationally driven about the axis, and the multi-threaded thread cutting blade 28 is moved inside the prepared hole 40. Cut into the peripheral surface. The amount of movement in the radial direction is 1/2 of the dimension obtained by subtracting the outer diameter d ₂ of the multi-threaded screw cutting blade 28 from the root diameter of the female screw to be formed. FIG. 4 (c) shows this state, in which a thread corresponding to the multi-threaded thread cutting blade 28 is formed on a part of the inner peripheral surface of the prepared hole 40, and a part of the chamfer 42 deletes an incomplete thread. It is cut and removed by the cutting edge 34. Subsequently, while the coupling tool 10 is rotationally driven about the axis, it is revolved once and a half revolutions about the center of the prepared hole 40 as shown by the arrow d, and the multi-threaded thread cutting blade 28 is rotated. Lifted 1.5 pitches above the thread. The revolving direction of the connecting tool 10 is a counterclockwise direction when viewed from above, which allows the threads of the multi-threaded thread cutting blade 28 to be formed on the inner peripheral surface of the prepared hole 40, as shown in (d) of FIG. A right-handed female thread 44 having a pitch equal to the pitch of is formed. Further, the incomplete whole mountain removing cutting edge 34 forms a cylindrical surface 46 having an inner diameter substantially the same as the root diameter of the internal thread 44 in a part of the chamfer 42, and the lower end opening of the internal thread 44, that is, the outlet side. The chamfering blade 32 chamfers the opening 48. Since the incomplete thread removing cutting edge 34 and the chamfering edge 32 that form the cylindrical surface 46 and the chamfer 48 are all connected to the top of the multi-threaded thread cutting edge 28, Thus, the formation of incomplete threads at both ends of the female screw 44 thus formed is prevented.

After that, the coupling tool 10 is moved to the center of the internal thread 44 as shown by the arrow e, and the rotation around the axis is stopped. FIG. 5E shows this state. Further, as shown by the arrow f, it is moved up to the initial position, which completes a series of female thread machining. FIG. 5F shows this state.

Here, in the coupling tool 10 of the present embodiment, since the outer diameter d ₂ of the multi-threaded thread cutting blade 28 is 90% or less of the outer diameter d ₁ of the drilling blade 20, the valley of the female screw 44 to be machined. When the ratio of the outer diameter of the multi-threaded thread cutting blade 28 to the diameter is small, and the inner diameter of the female screw 44 is about 95% of the root diameter, the outer diameter of the multi-threaded thread cutting blade 28 is about 85% of the female thread root diameter. When the inner diameter of the internal thread 44 is about 85% of the root diameter, the outer diameter of the multi-threaded thread cutting blade 28 is about 76% or less of the root diameter of the internal thread. As a result, the amount of interference cutting is reduced, and the amount of edge shape modification that takes into account the interference cutting can be made within a range that poses no practical problems in terms of strength.

The smaller the ratio of the outer diameter d ₂ of the multi-threaded thread cutting blade 28 to the outer diameter d ₁ of the boring blade 20, the smaller the amount of interference cutting, but the flexural rigidity and torsional strength of the tool The transverse rupture strength and the chip discharge performance deteriorate. On the other hand, in the coupling tool 10 of the present embodiment, since the outer diameter d ₂ of the multi-threaded thread cutting blade 28 is set in the range of 70% or more of the outer diameter d ₁ of the punching blade 20, the flexural rigidity and Torsional strength, transverse rupture strength, and chip ejection performance are maintained within practically acceptable ranges.

The hatched portion in FIG. 6 indicates the outer diameter d of the punching blade 20.₁Outer diameter d of the multi-threaded thread cutting blade 28 with respect to ₂ Of the multi-threaded thread cutting blade 28 with respect to the root diameter of the internal thread 44 in the connecting tool 10 of the present embodiment in which the ratio of 70 to 90% is defined.₂The solid line shows the case where the inner diameter of the female screw 44 is 95% of the root diameter, and the alternate long and short dash line shows the case where the inner diameter of the female screw 44 is 85% of the root diameter. Further, this FIG. 6 shows the outer diameter d of the punching blade 20.₁ Is the same as the inner diameter of the female screw 44, and the outer diameter d₁Is smaller than the inner diameter of the internal thread 44, the outer diameter d with respect to the root diameter of the internal thread 44₂The ratio is smaller and the amount of interference cutting is also smaller.

On the other hand, in the combined tool 10 of the present embodiment, a chamfering blade 36 having a maximum diameter larger than the outer diameter d ₁ of the boring blade 20 is provided on the rear side of the multi-threaded thread cutting blade 28 in the tool axial direction. As shown in FIG. 4 (a), the chamfer 42 is applied to the upper end opening of the prepared hole 40 continuously by the boring blade 20 so that the chamfer 42 is exclusively used for chamfering. Processing equipment and processing time are reduced compared to the case of using a tool.

Further, at the front end of the multi-threaded thread cutting blade 28 in the tool axial direction, a chamfering blade 32 having a diameter increasing toward the drilling blade 20 is continuous with the multi-threaded thread cutting blade 28 and the drilling blade 20. As shown in FIG. 4D, the chamfering 48 is applied to the lower end opening of the female screw 44 when the female screw 44 is cut by the multi-threaded thread cutting blade 28. As compared with the case of using a dedicated tool for chamfering, processing equipment and processing time are saved. Further, since the chamfer 48 chamfers the incomplete thread at the lower end opening, the life of the female screw 44 is prevented from being shortened due to such deformation or damage of the incomplete thread.

Further, at the rear end of the multi-threaded thread cutting blade 28 in the tool axial direction, there is a multi-threaded cutting edge 34 having an outer diameter equal to the outer diameter d ₂ of the multi-threaded thread cutting blade 28. As shown in FIGS. 4 (c) to 4 (d), which are provided continuously to the screw cutting blade 28, a part of the chamfer 42 is formed when the female screw 44 is cut by the multi-threaded screw cutting blade 28. Since the cylindrical surface 46 is formed to prevent the incomplete thread from being formed at the upper end opening, it is possible to prevent the life of the female screw 44 from being shortened due to such deformation or damage of the incomplete thread. It

Further, the length dimension L of the multi-threaded thread cutting blade 28 in the tool axial direction is set to be a dimension shorter than the wall thickness of the workpiece 30 by about 0.5 pitch, as shown in FIG. ), The cutting edge 34 for incomplete ridge removal enters the prepared hole 40 by about 1 pitch, and the tip of the multi-threaded thread cutting blade 28 prepares about 0.5 pitch by the prepared hole. As shown in (d) of FIG. 4, from the state where it projects downward from 40, it is revolved 1.5 revolutions in the circumferential direction of the prepared hole 40 while being moved upward by 1.5 pitches. Since the internal thread 44 is cut, the cylindrical surface 46 is cut by the incomplete ridge removing cutting edge 34 and the chamfer 48 is chamfered by the chamfering edge 32 during the cutting. To be done. Therefore, the processing time is shortened as compared with the case where the cylindrical surface 46 and the chamfer 48 are processed in another process.

Further, since the multi-threaded thread cutting blade 28 and the boring blade 20 are provided on the common land 18, the multi-threaded thread cutting blade 28 is reground by grinding the rake face, that is, the spiral groove 16. When this is done, the rake face of the outer peripheral blade 24 of the boring blade 20 is also ground and the outer peripheral blade 24 is retracted in the direction of narrowing the land 18, but the outer peripheral blade 24 has a margin 26. Therefore, even if the outer peripheral blade 24 retreats in the direction of narrowing the land 18, the outer diameter d ₁ thereof is maintained constant. As a result, the prepared hole 40 having a constant diameter is always cut regardless of the re-grinding of the multi-threaded cutting blade 28.

Although one embodiment of the present invention has been described in detail with reference to the drawings, the present invention can be implemented in other modes.

For example, in the above-described embodiment, the case where the coupling tool 10 is revolved counterclockwise as viewed from above and moved upward in the axial direction to machine the female screw 44 of the right-hand thread has been described. The feed direction in the axial direction can be changed appropriately.

Further, although the pair of twisted grooves 16 are provided in the above-described embodiment, the number of the twisted grooves can be appropriately changed, and a straight groove parallel to the axis may be provided. The number of multi-threaded thread cutting blades 28 and the number of perforation blades 20 do not necessarily have to be the same.

Further, the connecting tool 10 of the above-described embodiment is provided with the chamfering blades 32 and 36 and the incomplete mountain removing cutting edge 34, but these may be appropriately provided as necessary. The length dimension L of the multi-thread screw cutting blade 28 can also be set as appropriate.

Although not illustrated one by one, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

FIG. 1 is a front view of a through hole thread cutting coupling tool according to an embodiment of the present invention.

2 is a bottom view of the embodiment of FIG. 1. FIG.

FIG. 3 is a diagram showing a state in which the tool of FIG. 1 is positioned at an initial position with respect to a workpiece when performing internal thread machining.

FIG. 4 is a view showing each step when performing internal thread processing using the tool of FIG. 1 together with FIG.

FIG. 5 is a diagram showing, together with FIG. 4, steps for performing internal thread processing using the tool of FIG. 1.

6 is a diagram showing a ratio of an outer diameter of a multi-threaded thread cutting blade to a root diameter of a female thread in the tool of FIG.

FIG. 7 is a diagram for explaining the influence of the difference in the outer diameter of the multi-threaded thread cutting blade on the interference cutting, wherein (a) is 100 of the outer diameter of the drilling blade.
%, And (b) is 90%.

[Explanation of symbols]

10: Drilling screw cutting coupling tool for through hole 18: Land 20: Drilling blade 26: Margin 28: Multiple thread cutting blade 30: Work piece 32: Chamfering blade (second chamfering blade) 34: Cutting edge for incomplete thread removal 36 : Chamfering blade (first chamfering blade) 40: Prepared hole 44: Female screw d ₁ : Outer diameter of drilling blade d ₂ : Outer diameter of multi-thread screw cutting blade

Claims (6)

[Scope of utility model registration request] 1. A leadless multi-threaded thread cutting blade having a drilling blade for cutting a prepared hole at its front end in the axial direction and having a drilled hole formed by the drilling blade for cutting a female screw is more than the drilling blade. It is integrally provided on the rear side in the axial direction, and is driven to rotate about the axis while being relatively moved in the axial direction with respect to the workpiece, so that after the prepared hole is machined by the boring blade, it is driven to rotate about the axis. In the drilling threaded connection tool for through holes, wherein the internal thread of the prepared hole is machined by the multi-threaded thread cutting blade by being relatively moved in the prepared hole in the axial direction and the circumferential direction, The outer diameter of the thread cutting blade is 90% of the outer diameter of the punching blade.
A through hole threading coupling tool for through holes, characterized in that: 2. The relative diameter of the maximum diameter is larger than the outer diameter of the boring blade on the rear side in the tool axial direction with respect to the multi-threaded thread cutting blade and is relatively driven in the axial direction while being rotationally driven around the axis. The hole drilling thread cutting connection tool according to claim 1, wherein a first chamfering blade for chamfering is provided on the inlet side of the prepared hole. 3. When cutting a female screw with the multi-thread screw cutting blade, the maximum diameter of at least one of the front end and the rear end of the multi-thread screw cutting blade in the tool axis direction is larger than the outer diameter of the multi-thread screw cutting blade. The hole drilling thread cutting coupling tool according to claim 1 or 2, wherein a second chamfering blade for chamfering the opening portion of the prepared hole is continuously provided on the top of the multi-threaded thread cutting blade. 4. A multi-threaded thread cutting blade having an outer diameter substantially equal to the outer diameter of the multi-threaded thread cutting blade on at least one of a front end and a rear end in the tool axial direction of the multi-threaded thread cutting blade. The hole drilling threaded connection tool according to any one of claims 1 to 3, wherein the tool is continuously provided on the top of the blade. 5. The length dimension of the multi-threaded thread cutting blade in the tool axial direction is substantially the same as the wall thickness of the workpiece to be machined as an internal thread, according to any one of claims 1 to 4. Hole drilling threaded coupling tool for holes. 6. The multi-threaded thread cutting blade and the drilling blade are formed on a common land extending in the tool axial direction, and a margin is provided on the outer peripheral portion of the land of the drilling blade. As described in any one of 5, a hole drilling threaded coupling tool for holes.