JP5241196B2 - Thick tap for processing large diameter female thread - Google Patents

Description

  The present invention relates to a raised tap for machining a large-diameter female screw that plastically deforms a prepared hole of a workpiece material to form a female screw having a nominal size of M40 × 3 or more.

  The machining of large-diameter female threads with a nominal size of M40x3 or more has been conventionally performed using a cutting tap. However, cutting taps caused a large amount of chips, causing many problems such as increased tapping torque, mess on the internal thread surface, defects due to galling, and chipping due to chipping.

  By the way, since the development of NC (numerical control) machines with 3-axis control in recent years, female thread machining with threaded milling tips has become the mainstream instead of taps. However, even with this machining method, if the accuracy of the machine deteriorates, the internal thread accuracy will not reach the standard accuracy, or if the tool is chipped or worn, mess or galling will occur on the internal thread surface, resulting in a large amount after completion of processing. If the chip is removed and the finish of the internal thread is not confirmed, the next process will not proceed, so there is a problem that the operating rate of the expensive machine cannot be increased (for example, the nominal size is M64 × 3 and the effective thread length is 73 mm). It took 4 hours to process 35 large-diameter female threads).

  In order to eliminate such obstacles and improve productivity, there is no choice but to use a raised tap that does not generate chips, so its development is strongly influenced by a plant-related user to the applicant who is a tap manufacturer. I was asked to start.

  The raised tap has been used in the female thread processing industry for several decades, but the tapping torque is 2 to 3 times larger than that of the cutting tap, so non-ferrous metals, pure iron, etc. with relatively small deformation resistance It was limited to material processing. Recently, however, the raised tap has been recognized for its advantages such as the absence of chips and stable internal thread accuracy, and the surrounding environment has been improved, such as the tapping machine's rigidity, the development of chucks, and the improvement of cutting oil.・ Although the range of use has expanded to materials with large deformation resistance, such as alloy steel and stainless steel, the tapping torque is still large, so the nominal size of the internal thread is limited to the range of M20 × 2.5 ( Patent Document 1).

JP 2006-116764 A

  An object of the present invention is to provide a raised tap for processing a large-diameter internal thread that can effectively reduce an increase in tapping torque and perform internal thread processing with a nominal size of M40 × 3 or more in a short time.

In order to achieve the above object, a raised tap for processing a large-diameter female screw according to the present invention has a plurality of radial portions arranged in a screw shape on the outer periphery of a main body to form a male screw, and the main body is rotated in one direction. In a raised tap for processing a large-diameter internal thread that forms an internal thread having a nominal size of M40 × 3 or more by plastically deforming the inner peripheral surface of the material by the radial portion,
In the male screw, a bite portion gradually becoming a small diameter toward the tip, a complete crest portion, and a bite portion gradually becoming a small diameter toward the rear end are formed continuously in the axial direction,
The radial portion in the complete mountain portion has a radial portion that is thinned so that it is not in contact with the female screw at the time of tapping, when the number of radials is even, one in three or every other odd number. It is formed.

  Further, the length of the biting portion is approximately 4P.

  In addition, the length of the complete mountain portion is approximately 4 to 6P.

  The length of the after-eaten portion is approximately 1.5 to 2P.

  Further, the top of the thread of the male screw is rounded in an R shape.

  Further, the thread thread valley portion of the male screw is rounded in an R shape.

  The radiated radial portion is characterized in that approximately 0.01 to 0.05 mm is formed on both front and rear side surfaces.

  According to the present invention having the above-described configuration, the increase in tapping torque is reduced by the lean radial portion formed in the complete mountain portion, and the tap-in portion is continuously formed in the complete mountain portion. Smooth return and machining of large diameter female threads with a nominal size of M40 × 3 or more can be performed in a short time without generating chips.

  DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a thickening tap for machining a large-diameter female screw according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a side view of a raised tap for machining a large-diameter female screw according to an embodiment of the present invention, FIG. 2A is a front sectional view of a complete mountain portion, and FIG. 2B is a radial portion that is thin from the direction of arrow A in FIG. FIG. 3 is a schematic diagram, FIG. 3 is a diagram illustrating the shape of a complete thread, and FIG.

  As shown in FIGS. 1, 2A, and 2B, a large-diameter female thread machining tap is provided with a plurality (eight in the illustrated example) of radial portions 6a on the outer peripheral portion of the main body 1 made of high-speed steel (high speed) or the like. ˜6h are arranged in a screw shape (see angle θ≈3 ° in FIG. 2B), and the male screw 2 having a nominal size of M64 (mm) × 3 (mm) is formed.

  The male screw 2 has a bite portion 3 that gradually decreases in diameter toward the front (front) end, a complete crest portion (parallel screw portion) 4, and a bite portion 5 that gradually decreases in diameter toward the base (rear) end. Are continuously formed in the axial direction.

  Further, in the circumferential direction of the male screw 2, a plurality of strips (eight strips in the illustrated example) extending in the axial direction of the main body 1 are located in the intermediate portions of the relief drop portions 7a to 7h connecting the radial portions 6a to 6h. Groove portions 8a to 8h are formed. In FIG. 2A, D1 is a valley diameter, D2 is an effective diameter, D3 is an outer diameter, and W is a radial width.

  In this embodiment, the length of the bite portion 3 is 4P (pitch, four peaks), the length of the complete peak portion 4 is 4P (pitch, four peaks), and the length of the bite portion 5 is 2P. (Pitch, 2 ridges) and the screw length is set to 10P (Pitch, 10 ridges). In addition, the length of the complete peak part 4 may be about 4-6P, and the length of the postprandial part 5 may be about 1.5-2P.

Further, as shown in FIG. 4, the thread crest portion of the male screw 2 set to H / 8 or less is rounded to the R ₁ shape and the thread valley portion set to H / 4 or less is R ₂ shape. It is formed to curl up.

  Further, as shown in FIGS. 2A, 2B, and 3, the radial portions (threads) 6a to 6h of the complete thread portion 4 of the male screw 2 include regular radial portions (threads) 6a, 6b, 6d, Radial portions (screw threads) 6c and 6f which are located between 6e, 6g and 6h are formed. The radiated radial portions (threads) 6c, 6f are subjected to a dip process of approximately 0.01 to 0.05mm on the front and rear side surfaces (flank portions) so that they are not in contact with the female screw during tapping. It has become.

  In addition, as shown in FIGS. 2A and 2B, the radiated radial portions (threads) 6 c and 6 f are formed when, for example, eight (even) radial portions (threads) 6 a to 6 h are formed on the male screw 2. Is formed for every three mountains. In FIGS. 2A and 2B, 6c and 6f are radial portions (threads) where the outer diameter D3 and the valley diameter D1 are not changed, and only the effective diameter D2 is reduced. In addition, when the radial number is an odd number, it is preferable to form a radial portion (thread) that is ridged every other mountain.

  Because of this configuration, the inner peripheral surface of the material made of high-temperature high-pressure cast steel (SCPH) or the like is plastically deformed by the radial portions 6a to 6h using the raised tap, and the nominal size is M64 (mm) × 3, for example. When forming a female thread of (mm), the increase in tapping torque is reduced by the radiated radial parts 6c and 6f formed in the complete thread part 4 of the male thread 2, and the continuous thread part 4 is continuously connected to the complete thread part 4. The post-eating portion 5 formed in this way makes it possible to smoothly return the tap when it is reversed, and it can be processed in a short time (1 hole 2 minutes 30 seconds) without generating chips.

  That is, by forming the above-mentioned bite portion 5, the length of the complete peak portion 4 is formed to be as short as the length of the bite portion 3 so as to further reduce the increase in tapping torque. It is possible to effectively avoid the fact that the tap is not easily returned (unplugged) due to the influence of the shrinkage of the material.

  In addition to the thread crest portion set to H / 8 or less of the male screw 2, the thread valley portion set to H / 4 or less is formed in a rounded shape so that the increase in tapping torque is further reduced. In addition, the life of surface treatment such as coating can be extended.

  In this way, in the present embodiment, the tapping is performed by partially squinting the complete crest 4 of the male screw 2, setting the above-described length of the chamfered portion 3 and the complete chamfer 4, and newly providing the aftergrowth portion 5. The increase in torque and the return of taps were smoothed, enabling machining of large-diameter female threads with a nominal size of M64 (mm) x 3 (mm), which was previously impossible.

  According to the experiments by the inventors of the present application, for example, when machining at a tapping speed of about 5 m / min, a tapping torque of about 700 N · m is usually required. It has been elucidated that large-diameter female threads can be machined with torque.

  It should be noted that the present invention is not limited to the above-described embodiment, and various changes such as changes in the material of the main body, the nominal size of the male screw, and the number of radial portions and oil groove portions are possible without departing from the spirit of the present invention. Needless to say.

It is a side view of the rising tap for large diameter internal thread processing which shows one Example of this invention. It is a front sectional view of a complete mountain part. It is a schematic diagram of the radial part which faded from the A arrow view of FIG. 2A. It is shape explanatory drawing of a complete mountain part. It is shape explanatory drawing of a screw thread.

Explanation of symbols

1 Body of tap for processing large-diameter female thread 2 Male thread 3 Chamfer 4 Complete thread (parallel thread)
5 After-eating part 6a, 6b, 6d, 6e, 6g, 6h Regular radial part 6c, 6f Radial part with leaning

Claims (7)

A plurality of radial portions are arranged in a screw shape on the outer periphery of the main body to form a male screw, and the main body is rotated in one direction to plastically deform the inner peripheral surface of the material by the radial portion, so that the nominal size is M40 × In the rising tap for processing a large-diameter internal thread that forms 3 or more internal threads,
In the male screw, a bite portion gradually becoming a small diameter toward the tip, a complete crest portion, and a bite portion gradually becoming a small diameter toward the rear end are formed continuously in the axial direction,
The radial portion in the complete mountain portion has a radial portion that is thinned so that it is not in contact with the female screw at the time of tapping, when the number of radials is even, one in three or every other odd number. A raised tap for machining a large-diameter internal thread characterized by being formed.   The raised tap for machining a large-diameter internal thread according to claim 1, wherein the length of the biting portion is approximately 4P.   2. The raised tap for machining a large-diameter female screw according to claim 1, wherein the length of the complete mountain portion is approximately 4 to 6P.   2. The raised tap for processing a large-diameter internal thread according to claim 1, wherein a length of the after-eaten portion is approximately 1.5 to 2P.   2. A raised tap for machining a large-diameter female screw according to claim 1, wherein a screw thread top portion of the male screw is rounded in an R shape.   The raised tap for machining a large-diameter female screw according to claim 1, wherein a thread valley portion of the male screw is rounded in an R shape.   The raised tap for machining a large-diameter internal thread according to claim 1, wherein the radiated radial portion is subjected to an approximately 0.01-0.05 mm ridge process on both front and rear sides.

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