JP6941294B2 - Manufacturing method of multi-threaded female thread and tap tool - Google Patents

Description

The present invention relates to a method for manufacturing a multi-threaded female thread and a tap tool for forming a female thread having a plurality of threads by performing female thread processing on a work having a prepared hole formed in advance using a tap tool.

Conventionally, as a technique relating to a method for manufacturing a multi-row female screw having a plurality of threads, for example, there is one described in Patent Document 1 below.

The technique described in Patent Document 1 is to form a multi-row female thread in a material by screwing a columnar tap tool having a spiral thread on the outer peripheral surface into a pilot hole of the material. The tap tool used here has blades that are smaller than the number of female threads formed in the material, and the spacing along the circumferential direction of each blade is 360 ° divided by the number of female threads. It is set to a multiple of.

This tap tool is screwed into a pilot hole formed in the material, and a thread groove smaller than the planned number of threads is formed in the material. Following this, the tap tool is rotated so that each blade of the tap tool is located on the inner peripheral surface of the hole where the female thread is not formed. The rotation angle is a multiple of the value obtained by dividing 360 ° by the number of female threads to be formed. By screwing the tap tool into the prepared hole in this state, a female screw is formed in the remaining area.

As described above, the technique of Patent Document 1 is to reduce the machining resistance of the tap tool by forming multiple female threads while subdividing the number of threads to be machined.

Japanese Unexamined Patent Publication No. 2008-284571

However, in the manufacturing method and tap tool described in Patent Document 1, the number and arrangement of blades to function in one machining are not specified. For example, the number of blades is simply less than the number of female threads. The arrangement interval of the blades along the circumferential direction is only a multiple of the value obtained by dividing 360 degrees by the number of female threads. Therefore, for example, as shown in FIG. 2 of Patent Document 1, when the number of rows is 5, the blades of 3 rows may be gathered at one place on the circumference.

When the material is machined with such a tap tool, the machining load is concentrated on a part of the area along the circumferential direction of the tap tool, so that the tap tool is easily bent and deformed, and the machining accuracy of the female screw is deteriorated.

Further, when the number of threads of the tap tool blade is set to 3 when forming 5 female threads, in the second machining, one of the tap tool blades is one of the screw grooves formed in the first machining. It will be processed by stacking one. In this case, the shape of the thread groove that has already been machined may be disturbed, and the shape of the thread groove of each strip may become non-uniform.

In this way, although the conventional method for manufacturing multi-threaded female threads improves the processing work such as reducing the processing resistance, there is still room for improvement as to whether or not high-precision multi-threaded female threads are always formed. rice field.
For this reason, conventionally, there has been a demand for a method for manufacturing a multi-threaded female screw and a tap tool having excellent machining accuracy while reducing machining resistance during machining.

(Characteristic composition)
The characteristic configuration of the method for manufacturing a multi-row female screw according to the present invention is as follows.
When forming a female thread with the number of threads J,
For workpieces with prepared holes
It is provided with a Y-row blade for processing a thread groove for a divisor Y, which is a natural number larger than 1 of the number J and smaller than J, and the Y-row blade is formed so as to be point-symmetric with respect to the axis. Insert the tap tool and
The tap tool and the work are subjected to basic machining in which the tap tool and the work are relatively rotated around the shaft core and relatively moved along the shaft core to form the female screw of the Y-row on the work. Is relatively rotated around the axis by a multiple of (360 / J) degrees to position the blade in the prepared hole where the formation of the female screw has not been completed (J / Y). ) It is a point to do it once.

(effect)
Since the tap tool used in this manufacturing method has a blade having a number of threads Y, which is smaller than the number of threads J of the thread groove formed on the female thread, the machining resistance generated during one basic machining is reduced. Therefore, deformation such as the tap tool being twisted by machining resistance is reduced, and the machining accuracy of the female screw is improved. Further, since the machining resistance is reduced, the required torque of the machining device is also small, and the machining of the multi-threaded female thread can be performed efficiently.

Further, in the tap tool used in this manufacturing method, the blades for Y rows are arranged so as to be point-symmetric with respect to the axis. Therefore, since the machining resistance acting on the tap tool during machining is distributed in a well-balanced manner around the shaft core, the tap tool does not bend and deform during machining, and an accurate thread groove can be formed.

Moreover, since the number of blades formed in the tap tool is about the divisor Y of the number J of female threads formed in the work, the shape of the thread groove already formed is disturbed when the basic machining is performed in a plurality of times. Processing can proceed so that there is no such thing. Therefore, the accuracy of all the thread grooves formed is improved, and a high-quality multi-threaded female thread can be obtained.

(Characteristic composition)
In the method for manufacturing a multi-row female screw according to the present invention, the tap tool is provided with the blade of the Y-row as a second blade in a grip portion for gripping the tap tool and a region adjacent to the grip portion. The second blade has an outer diameter smaller than the outer diameter of the second blade in a region adjacent to the second blade on the opposite side of the grip to the second blade. The first blade has a number K which is a natural number of the number J or less, which is larger than the number of the second blades including those having continuous blade lines, and is arranged point-symmetrically with respect to the axis. It is convenient to have a first blade portion provided with the above.

(effect)
When the tap tool of this method is used, a thread groove is first formed by a first blade formed at the tip of the tap tool when performing one basic machining. The outer diameter of the first blade is set smaller than that of the second blade, and does not completely form the tooth bottom of the female screw. The first blade is arranged point-symmetrically with respect to the axis, and the machining resistance acting on the tap tool is arranged around the axis in a well-balanced manner. Further, since the number K of the first blade is larger than the number of the second blades and may be a natural number equal to or less than the number J of the female threads, the number and arrangement of the first blades are appropriately set according to the shape of the female threads and the like. can do.

Following the machining of the first blade, the second blade performs machining. The second blade machined the Y-threaded thread groove, which is a part of the J-threaded thread groove, and completely processed up to the tooth bottom to be formed.

By machining K threads with the first blade with a small outer diameter, the first blade of the tap tool whose rotation phase was changed during the second basic machining is the thread groove formed in the first basic machining. Guided by. In the first basic machining, only the Y-row thread groove is completely machined by the second blade, but the other thread grooves are only shallowly machined by the first blade. Therefore, even if the first blade whose phase has been changed follows each thread groove when performing the second basic processing, the first blade is a screw whose finish processing has been completed in the previous basic processing. Does not contact many areas of the groove.

In this way, by using the tap tool of this configuration, even if the thread grooves for Y threads are divided and formed, the finishing process for each thread groove is performed once, and a highly accurate multi-thread female thread is formed. be able to.

Further, by using the tap tool having this configuration, the phase of the tap tool is surely set in the second and subsequent basic machining, and the dependence on the machining machine for the phase setting of the tap tool is relaxed. Therefore, the cost of the processing equipment can be reduced, and a highly accurate multi-threaded female screw can be efficiently obtained.

(Characteristic composition)
The characteristic configuration of the tap tool for multi-threaded female thread machining according to the present invention is as follows.
A blade and a grip are provided to form a multi-threaded female screw with a number of threads J.
The blade is
The second blade of the Y-row, which processes a thread groove for about a divisor Y, which is a natural number larger than 1 of the number J and smaller than J, is adjacent to the grip portion in a state of being point-symmetric with respect to the axis. The second blade part provided in the area to be
In the region adjacent to the second blade portion on the side opposite to the grip portion, the outer diameter dimension is smaller than the outer diameter dimension of the second blade, and the blade line continuous with the second blade is provided. A first blade having a number K which is a natural number of the number J or less, which is larger than the number of the second blades including those, and provided with a first blade arranged point-symmetrically with respect to the axis. It is in the point that it has a part and.

(effect)
The tap tool having this configuration is provided with only Y threads, which is smaller than the number of J threads to be formed, as the second blade, and the machining resistance can be reduced. Moreover, since the second blade for the Y row is provided point-symmetrically with respect to the shaft core, the generation of machining resistance is dispersed around the shaft core in a well-balanced manner. Therefore, the tap tool is not bent or twisted during machining, and a highly accurate multi-threaded female thread can be formed.

Further, when the tap tool having this configuration is used, in the first machining, a shallow thread groove is formed by the first blade having the number of threads K, which is a natural number of J or less, which is formed at the tip and is larger than the number of the second blades. Is formed, and by the subsequent processing of the second blade, the thread groove for Y threads is completely finished up to the tooth bottom to be formed.

By machining K-row thread grooves with the first blade having a small outer diameter, the first blade follows each thread groove during the second machining. In this case, the first blade does not come into contact with most of the threaded groove for which the finishing process has been completed. That is, in the second and subsequent machining, the phase of the tap tool is surely set, and the second and subsequent machining becomes accurate.

By using the tap tool of this configuration in this way, even when multi-threaded female threads are divided and formed for each Y-threaded thread groove, the finishing process to complete each thread groove can be done only once with high accuracy. Female threads can be formed. Further, since the dependence of the phase setting of the tap tool on the driving accuracy of the machining machine is relaxed, the cost of the machining equipment can be reduced, and a highly accurate multi-threaded female thread can be efficiently obtained.

External view showing a tap tool according to the first embodiment Explanatory drawing which shows the manufacturing procedure of the multi-row female screw which concerns on 1st Embodiment External view showing a tap tool according to a second embodiment Explanatory drawing which shows the manufacturing procedure of the multi-row female screw which concerns on 2nd Embodiment Explanatory drawing which shows the structural example of the blade part in the tap tool of 2nd Embodiment

[First Embodiment]
The first embodiment of the tap tool T for processing the multi-row female screw M and the method for manufacturing the multi-row female screw M according to the present invention will be described with reference to FIGS. 1 and 2. FIG. 1 is an external view showing a tap tool T, and FIG. 2 is an explanatory view showing a manufacturing procedure of a multi-threaded female screw M.

(Appearance of tap tool)
In this embodiment, for example, an example in which four (M1 to M4) multi-threaded female threads M are cut and formed on the work W is shown. As shown in FIG. 1, the tap tool T used in the present embodiment has a grip portion H formed on the base end side so as to be gripped by a machine tool or the like, and a work W provided adjacent to the grip portion H. It is provided with a blade portion E for cutting and processing.

The blade portion E is formed with blades E21 and E23 for two blades, for example, half of the four blades J, which is the number J of the multi-threaded female screw M to be formed. These two blades E21 and E23 are arranged symmetrically with respect to each other with the axis X, which is the center of rotation, interposed therebetween. If it is symmetrical, the machining resistance at the time of machining acts in a well-balanced manner in the circumferential direction with the axis X as the center. Therefore, the tap tool T does not bend and deform during machining, and the rotational posture is not disturbed, so that the machining accuracy of the work W is improved.

As described above, the tap tool T of the present embodiment is provided with a blade E2n having a small number of threads Y with respect to the number of threads J of the multi-threaded female screw M to be produced. However, when forming the multi-threaded female screw M having the number of threads J, the number of threads Y of the blade E2n provided in the tap tool T is a divisor of the number of threads J, and is a natural number larger than 1 and smaller than J. As a result, the number of times of machining by the tap tool T becomes (J / Y), and the waste of finishing machining in which any of the thread grooves Mn overlaps is eliminated. In addition, each processing is hereinafter referred to as basic processing.

(Manufacturing procedure for multi-row female screw)
2 (a) to 2 (d) show the manufacturing procedure of the multi-row female screw M according to the first embodiment. Here, a case is shown in which a tap tool T provided with two blades E21 and E23 is used in order to form a four-row multi-thread female screw M in a work W in which a prepared hole M0 is machined in advance. 2 (a) and 2 (b) are explanatory views relating to the first basic machining, and FIGS. 2 (c) and 2 (d) are explanatory views relating to the second basic machining. In the normal tap tool T, in order to facilitate cutting into the work W, a tapered portion is provided in the vicinity of the tip portion so that the outer dimension becomes smaller as the tip portion approaches the tip portion.

FIG. 2A shows a state immediately after the tap tool T starts cutting into the prepared hole M0 of the work W in the first basic machining. After that, the tap tool T is rotated around the shaft core X and fed along the shaft core X. At this time, the relative rotation speed between the tap tool T and the work W and the feed speed of the tap tool T along the axis X are preset according to the pitch of the multi-threaded female screw M to be formed.

FIG. 2B shows a state in which two thread grooves M1 and M2 are formed up to the end of the prepared hole M0 of the work W in the first machining. Since the number of thread grooves M1 and M3 having two threads to be machined is small, the machining resistance acting on the tap tool T is small. Therefore, the required rotational torque of the processing machine is small, the holding force of the work W is also small, and a large-scale processing machine is not required. Further, since the number of processing rows is small, the heat generated by the work W is small during processing, and the deformation of the work W and the change in mechanical properties due to heat can be minimized.

FIG. 2C shows a state in which the blades E21 and E23 are cut into the starting end of the prepared hole M0 of the work W in the second machining. After the completion of the first basic machining, the tap tool T is rotated relative to the work W by a multiple of (360 / J) degrees around the axis X, that is, 90 degrees, and the blades E21 and E23 are rotated. Is positioned in the prepared hole M0 where the formation of the multi-threaded female screw M is not completed. At this time, the processing machine and the gripping device of the work W (not shown) grasp their own postures, and the relative angle between the tap tool T and the work W is set accurately.

FIG. 2D shows a state in which the second basic machining has been completed. As a result, four multi-threaded female threads M are formed on the work W.

By machining the number of threads Y, which is smaller than the number of threads J of the thread groove Mn formed in the multi-threaded female thread M, the machining load in one basic machining is reduced, and the tap tool T and the work W can be machined. Deformation and alteration are prevented, and a multi-row female screw M having an accurate shape is formed. The processing machine and the gripping device for the work W are also simplified, and the processing of the multi-threaded female screw M becomes efficient.

Moreover, since the number Y of the blade E2n formed on the tap tool T is a divisor of the number J of the multi-thread female screw M formed on the work W, it has already been formed when the basic machining is performed in a plurality of times. The shape of the thread groove Mn is not disturbed. Therefore, the accuracy of all the formed thread grooves Mn is improved, and a high-quality multi-threaded female thread M can be obtained.

[Second Embodiment]
The second embodiment of the tap tool T for processing the multi-row female screw M and the method for manufacturing the multi-row female screw M according to the present invention will be described with reference to FIGS. 3 and 4. Here, too, the number J of the multi-threaded female screw M is set to 4.

(Appearance of tap tool)
FIG. 3 shows the appearance of the tap tool T according to the second embodiment. The first blades E11 to E14 for four rows to be machined are formed at the tip of the blade portion E on the machining start side. This region is referred to as the first blade portion E1. A second blade portion E2 is formed on the side of the grip portion H continuously with the first blade portion E1. The second blade portion E2 here has two second blades, E21 and E23. The second blades E21 and E23 are the same as the blades E21 and E23 in the first embodiment.
The two second blades E21 and E23 are continuously formed on the first blades E11 and E13. All the first blades E11 to E14 are formed at point-symmetrical positions about the axis X, and the two second blades E21 and E23 are also point-symmetrical with respect to the axis X.

As shown in FIG. 3, the first blades E11 to E14 are formed in a tapered portion at the tip portion, and the external dimensions of the first blades E11 to E14 are smaller than the outer diameter dimensions of the second blades E21 and E23. It is done. Thereby, for example, the depth of the thread grooves M1 to M4 machined by the first blades E11 to E14 is set to a fraction of the depth of the completed thread grooves M1 to M4. By doing so, the machining resistance generated by the first blade portion E1 can be reduced, and the machining resistance in each basic machining can be suppressed to a low level.

(Manufacturing procedure for multi-row female screw)
The manufacturing procedure of the multi-threaded female screw M is shown in FIGS. 4 (a) to 4 (d). FIG. 4A shows a state in which the tap tool T is made to bite into the prepared hole M0 of the work W. As shown in FIG. 4A, by forming all four first blades E11 to E14 on the first blade portion E1, four thread grooves to be formed at the start of the first basic machining. All positions of M1 to M4 can be specified in the work W.

FIG. 4B shows a state in which the tap tool T is machined with the pilot hole M0 of the work W by the second blade portion E2. In the first basic processing, only the thread grooves M1 and M3 are finished.

FIG. 4C shows a state in which the tap tool T is made to bite into the work W during the second basic machining. At this time, the phase of the tap tool T is changed by 90 degrees. As a result, for example, the thread grooves M2 and M4 in the process of being formed formed by the first blades E12 and E14 serve as a guide when cutting the tap tool T in the second basic machining, and the thread grooves M2 and M4 are again in phase. It serves as a guide for the first blades E11 and E13.

FIG. 4D shows a state in which the tap tool T is pulled out from the work W after the second basic machining is completed. As a result, the thread grooves M1 to M4 are finished in the work W.

In the case of the present embodiment, in the second basic machining, the thread grooves M2 and M4 formed in the first basic machining are not excessively machined. When the tap tool T is brought into contact with the work W in the second basic machining, for example, by loosening the fixing of the rotation phase of the machining machine that grips the tap tool T, the positions of the first blades E11 and E13 are set to the screw grooves M2. This is because it can be accurately aligned with M4.

Further, in the second basic machining, the first blades E11 and E13 imitate the thread grooves M2 and M4 finished in the first basic machining, but compared with the depth of the thread grooves M2 and M4. Since the heights of the first blades E11 and E13 are low, the areas of the surfaces of the thread grooves M2 and M4 that may be reworked by the first blades E11 and E13 are limited. Therefore, the thread groove Mn once finished and formed is not disturbed by the basic processing from the next time onward, and a multi-threaded female screw M having a good finished state can be obtained. Moreover, even when the processing of the multi-threaded female screw M is divided into a plurality of times, the relative positions of the thread grooves Mn formed in each are accurately set, so that a highly accurate multi-threaded female screw M can be obtained.

Further, in terms of machining resistance, in the second basic machining, the first blades E11 to E14 only follow the thread grooves M1 to M4 formed in the first basic machining, and only the second blades E21 and E23. Performs new processing. Therefore, the machining resistance generated in the second basic machining is smaller than that in the first basic machining involving the machining by the second blades E21 and E23 and the machining by the first blades E11 to E14.

That is, in the second basic machining, when the two second blades E21 and E23 perform machining with low machining resistance, the four first blades E11 to E14 are the screws formed in the first basic machining. Since the grooves M1 to M4 are imitated respectively, the machining positions by the second blades E21 and E23 are extremely accurate. Therefore, by using the tap tool T of the present embodiment, the machining of the multi-thread female screw M becomes efficient and highly accurate.

(Forms of forming the first blade and the second blade)
When the tap tool T having the first blade portion E1 and the second blade portion E2 is configured, the following conditions are required for the configuration of each blade portion. For example, FIG. 5 shows a configuration example of the first blade portion E1 and the second blade portion E2 when the number of rows J is 8.

The number of threads Y of the second blade portion E2 is a natural number of 2 or more and less than the number of threads J = 8 because the thread grooves Mn are not duplicated and finished by the basic processing by the second blade portion E2 a plurality of times. Therefore, it is a divisor of the number J. Therefore, in this case, the number Y of the second blade portion E2 is 2 or 4. The respective second blades E2n forming the second blade portion E2 are arranged point-symmetrically with respect to the axis X.

On the other hand, the conditions for forming the first blade portion E1 are that all the second blades E2n are continuous and that they can be arranged point-symmetrically with respect to the axis X. Therefore, the number K of the first blade portion E1 is a natural number larger than the number Y of the second blade portion E2 and the number of rows J = 8 or less. In this case, the following variations can be obtained depending on the case where the number of rows Y = 2 of the second blade E2n and the case where the number of rows Y = 4.

FIG. 5 schematically shows the positions of the first blade E1n (black circle) and the second blade E2n (white circle) formed on the outer peripheral surface of the tap tool T. Of these, FIGS. 5A to 5E are cases where the number of rows Y = 2 of the second blade E2n. 5 (a) and 5 (b) show the case where the number of rows K = 4 of the first blade E1n, FIGS. 5 (c) and 5 (d) show the number of rows K = 6, and FIG. 5 (e) shows the number of rows K = 4. This is the case when it becomes 8.

On the other hand, when the number of rows of the second blade E2n is Y = 4, the number of rows of the first blade E1n is K = 6 as shown in FIGS. As shown in, the number of rows K = 8 may be obtained.

With such a configuration, the phase of the tap tool T is changed by an integral multiple of (360 / number J) after the first basic machining is completed, so that the first blade E1n is used in the first basic machining. The second basic processing can be performed using the thread groove Mn formed by the above as a guide portion. In that case, the thread groove Mn finished by the second blade E2n in the first basic machining is not duplicated in the second basic machining, and a multi-thread female screw M with good finishing accuracy can be obtained.

The method for manufacturing the tap tool T and the multi-row female screw M according to the above embodiment is not limited to the tap tool T for cutting, and can also be applied as the tap tool T for rolling.

The present invention is widely applied to a method for manufacturing a multi-threaded female thread and a tap tool for forming a multi-threaded female thread having a plurality of threads by threading a workpiece having a prepared hole in advance using a tap tool. Can be done.

E1 1st blade E1n 1st blade E2 2nd blade E2n 2nd blade En Blade H Grip part J Number of threads K Number of threads M Multi-thread female screw M0 Pilot hole Mn Thread groove T Tap tool W Work X Shaft core Y Number of threads

Claims (3)

When forming a female thread with the number of threads J,
For workpieces with prepared holes
It is provided with a Y-row blade for processing a thread groove for a divisor Y, which is a natural number larger than 1 of the number J and smaller than J, and the Y-row blade is formed so as to be point-symmetric with respect to the axis. Insert the tap tool and
The tap tool and the work are subjected to basic machining in which the tap tool and the work are relatively rotated around the shaft core and relatively moved along the shaft core to form the female screw of the Y-row on the work. Is relatively rotated around the axis by a multiple of (360 / J) degrees to position the blade in the prepared hole where the formation of the female screw has not been completed (J / Y). ) Manufacturing method of multi-threaded female screw to be performed. The tap tool
A grip portion that grips the tap tool and
A second blade portion in which the blade of the Y-row is provided as a second blade in a region adjacent to the grip portion,
In the region adjacent to the second blade portion on the side opposite to the grip portion, the outer diameter dimension is smaller than the outer diameter dimension of the second blade, and the blade line continuous with the second blade is provided. A first blade having a number K which is a natural number of the number J or less, which is larger than the number of the second blades including those, and provided with a first blade arranged point-symmetrically with respect to the axis. The method for manufacturing a multi-threaded female screw according to claim 1, further comprising a part. A blade and a grip are provided to form a multi-threaded female screw with a number of threads J.
The blade is
The second blade of the Y-row, which processes a thread groove for about a divisor Y, which is a natural number larger than 1 of the number J and smaller than J, is adjacent to the grip portion in a state of being point-symmetric with respect to the axis. The second blade part provided in the area to be
In the region adjacent to the second blade portion on the side opposite to the grip portion, the outer diameter dimension is smaller than the outer diameter dimension of the second blade, and the blade line continuous with the second blade is provided. A first blade having a number K which is a natural number of the number J or less, which is larger than the number of the second blades including those, and provided with a first blade arranged point-symmetrically with respect to the axis. A tap tool that has a part and.

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