WO2011078365A1 - Method for manufacturing screw, whirling cutter, and screw manufacturing device - Google Patents

Abstract

Provided is a method for manufacturing a screw which is capable of solving a problem due to rolling or cutting and prevents the movement path of an insert (13) from interfering with a desired curve line of the screw at the time of exiting and entering the curve line, thereby providing an intended curve line to the screw by a thread whirling process. In the method for manufacturing the screw, in the case where a lead angle and an attachment angle (β) of the screw are different from each other, the attachment angle is determined from the following equation. Attachment angle = tan^-1{n*pitch/(π*D1)} D1 = {(screw core diameter + screw outside diameter)/2} + ∆T screw core diameter ≤ D1 ≤ screw outside diameter In the case where ∆T > 0 is satisfied, {(screw outside diameter - screw core diameter)/2}*0.2 < ∆T < {(screw outside diameter - screw core diameter)/2} In the case where ∆T < 0 is satisfied, -{(screw outside diameter - screw core diameter)/2} < ∆T < -{(screw outside diameter - screw core diameter)/2}*0.2 where D1≠0, ∆T≠0, and n is the number of threads

Description

Screw manufacturing method, Waring cutter, and screw manufacturing apparatus Cross-reference of related applications

This international application claims priority based on Japanese Patent Application No. 2009-294915 filed with the Japan Patent Office on December 25, 2009, and the Japanese Patent Application No. 2009-294915 The entire contents are incorporated into this international application.

The present invention relates to a screw manufacturing method using a thread whirling processing method, a waring cutter used in the thread whirling processing method, and a screw manufacturing apparatus. Therefore, the present invention can be applied to the field of manufacturing general screws such as medical screws, worm screws, and metric screws.

Conventionally, when a general screw (mechanical screw) is manufactured, for example, a method by rolling is known. In the case of this rolling, a rolling die corresponding to a specific screw shape is used, which is preferable when a single product is manufactured in large quantities.

In addition to rolling, a method of manufacturing a screw by cutting is known. This cutting method is a method of cutting with a cutting tool while rotating a workpiece, and is suitable for manufacturing a small variety of products.

In addition to these screw manufacturing methods, for example, a thread whirling process is known as one of methods for producing medical screws such as implant screws and bone screws (see Patent Document 1). ).

This thread whirling is a main rotating tool that holds an annular whirling cutter that is fixed to a tool spindle of a lathe and that can rotate around a rotation axis, and a processing rod (workpiece) that is a raw material for manufacturing screws. This is a method for producing a screw using a spindle.

Specifically, using a Waring cutter in which a plurality of inserts are radially arranged, the workpiece held by the main spindle is inserted into the center through hole of the Waring cutter, and the Waring cutter is set at a predetermined angle with respect to the center axis of the workpiece. (Mounting angle) Tilt. In this state, the workpiece is advanced in the axial direction while rotating the workpiece in a predetermined direction, and at the same time, the warping cutter is rotated at a rotation speed larger than the rotation speed of the workpiece, and the thread is cut by one or a plurality of inserts. Is the method.

In addition, the mounting angle set in the above thread whirling process is generally equal to the lead angle in the screw design drawing.

US Pat. No. 6,877,934

However, when a screw is manufactured by rolling as described above, a rolling die corresponding to a specific screw shape is used, which is not suitable for manufacturing a small variety of products.
In addition, when a screw is manufactured by cutting, it is cut with a cutting tool. Therefore, it is difficult to cut the thread in one pass due to the cutting load, and the thread is formed in a plurality of times. Therefore, processing takes time. In particular, when manufacturing a long screw, it is difficult to perform cutting at a time, and it is necessary to form the screws in order, such as forming several peaks and then forming the next few peaks. Therefore, since it connects and processes, there existed a problem that the processing precision of the connected part was bad.

Furthermore, in the case of medical screws, the difference between the root diameter and the outer diameter is larger than that of screws used in general machines, and the shape of the screw thread (perpendicular to the direction in which the screws continue). Since there are special circumstances such as the fact that the cross-sectional shape is special, there were the following problems during the processing.

Specifically, as described above, when the mounting angle and the lead angle in the thread whirling process are made equal, it is difficult to produce a screw having a desired shape depending on the target work shape (screw shape). It was.

The first reason why it is difficult to obtain the desired screw shape is that the medical screw has a special shape. Secondly, thread whirling machining is a machining method using a rotating tool in which the insert is attached toward the center of the whirling cutter and this rotates, so the path of the insert (machining path) interferes with the curve curve of the screw. Because it will do. In other words, it is considered that when the insert enters and leaves the workpiece, the portion that should not be cut is also cut.

In other words, it was a problem that both the up and down cuttings were cut (triangular gray portion = interference portion on both the outer diameter side and the valley side of the screw as shown in FIG. 23). In other words, if interference occurs on both the screw outer diameter side surface and the screw base end side (valley side) side surface, it is difficult to tighten the screw with high accuracy, and further, the screw may become loose. .

However, if the interference occurs on either the screw outer diameter side surface or the screw base end side (valley side) side surface, there is no significant problem in using the manufactured screw.
The above-mentioned problems due to interference appear prominently when manufacturing specially shaped screws such as medical screws, but similar problems may occur with other common screws.

The present invention has been made in view of these problems, and can solve the problems caused by rolling and cutting, and suppress the interference of the path of the insert when entering and entering the desired curve curve of the screw, It is an object of the present invention to provide a screw manufacturing method by thread whirling having a desired curve curve, a waring cutter used for thread warping, and a screw manufacturing apparatus.

-1st aspect of this invention made | formed in order to achieve the said objective WHEREIN: Several inserts are arrange | positioned radially, the cyclic | annular cutter member (for example, Waring cutter) which can be rotated centering on a rotating shaft, and a medical screw A holding part (for example, a main spindle) that holds and rotates a workpiece for forming a workpiece, and the cutter member is inclined at a predetermined angle (mounting angle) with respect to the axis center of the workpiece, and the medical In the screw manufacturing method for manufacturing a screw, when the lead angle and the mounting angle of the medical screw are different, the mounting angle is expressed by the following formulas (1), (2), (3), (4), It is obtained by (5).

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
When ΔT> 0,
{(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
<{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
When ΔT <0,
-{(Screw outer diameter-Thread root diameter) / 2} <ΔT
<-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
However, D1 ≠ 0, ΔT ≠ 0, n is the number of threads In the screw manufacturing method of the present invention, for example, when the lead angle of the medical screw is designed to satisfy the following formula (X) or Even in a special shape, when the workpiece and the cutter member are rotated, the insert is less likely to interfere with the medical screw as shown in Tables 1 to 3 of the first to third embodiments described later.

Specifically, when the mounting angle is made smaller (shallow) than the lead angle (that is, 0 <ΔT), it is difficult to hit the side surface of the tip of the screw thread. On the other hand, if the mounting angle is larger (deeper) than the lead angle (that is, 0> ΔT), it is difficult to hit the side face of the base end of the screw thread. Here, ΔT indicates the adjustment range of the mounting angle.

Below, each formula mentioned above is explained.
As shown in the above equation (3), D1 has a minimum thread valley diameter and a maximum screw outer diameter. As shown in the above equation (2), when D1 = the thread valley diameter, ΔT = (screw valley diameter) − {(screw valley diameter + screw outer diameter) / 2}. . Similarly, when D1 = the outer diameter of the screw, ΔT = (the outer diameter of the screw) − {(the diameter of the screw valley + the outer diameter of the screw) / 2}. Therefore, when D1 is the diameter of the thread valley or the outer diameter of the screw, the variation width ΔT with respect to {(the diameter of the thread valley + the outer diameter of the screw) / 2} is the maximum value (also referred to as the maximum variation width). .
Here, regarding D1, the value of D1 between the minimum value and the effective diameter and the value of D1 between the effective diameter and the maximum value will be described.
By setting the time of ΔT = maximum fluctuation range as 100% of fluctuation, the value of ΔT with fluctuation of 0 to 100% can be calculated. Specifically, when the fluctuation is 50%, ΔT = maximum fluctuation width / 2. The value of ΔT determined in this way can be applied to the above equation (2) to determine the value of D1 between the minimum value and the effective diameter, and the value of D1 between the effective diameter and the maximum value. Then, the obtained D1 can be applied to the above equation (1) to calculate the mounting angle.
Further, as shown in Tables 1 to 3 of the first to third embodiments described later, by setting the range of ΔT to the above formulas (4) and (5), the insert is less likely to interfere with the medical screw.

Lead angle = tan ⁻¹ {n × pitch / (π × effective diameter)} (X)
However, effective diameter = {(diameter of screw valley + external diameter of screw) / 2}, n is the number of threads Here, “n × pitch (P)” is a value called a lead (L), This is the distance traveled when the screw makes one revolution. The effective diameter (D) is defined by JIS B0101 1215, the lead angle is defined by JIS B0101 1208, and the pitch is defined by JIS B0101 1206. Other terms also have meanings defined in JIS. In addition, it is common for those skilled in the art to use an effective diameter for calculation of a lead angle. (The same applies hereinafter)
Therefore, according to the present invention, it is possible to manufacture a screw having a desired curve curve by suppressing the movement path of the insert from interfering with the curve curve of the desired screw both when entering and entering. .

In other words, in the present invention, interference can be prevented from occurring on both sides of the screw outer diameter side surface and the screw base end side (valley side) side surface. Can be rotated. That is, it does not become a big problem when using the manufactured screw.

Here, the interference at the time of entering means the interference when the insert enters the screw curve curve when machining the screw, and the interference at the time of exiting means the interference when the insert goes out of the curve curve of the screw. Say.

Also, in the present invention, it is possible to easily produce a small amount and a wide variety as compared with rolling. Furthermore, as compared with cutting, the machining time can be shortened, and a single workpiece can be continuously machined. Therefore, there is an advantage that it is not necessary to machine them together and machining accuracy is high.

-Moreover, the 2nd aspect of this invention can arrange | position several inserts radially, and can hold | maintain and rotate the cyclic | annular cutter member which can be rotated centering | focusing on a rotating shaft, and the workpiece | work for forming a worm screw. In a screw manufacturing method for manufacturing a worm screw by inclining the cutter member by a predetermined angle (attachment angle) with respect to the axis center of the workpiece using a holding portion, the lead angle and the attachment angle of the worm screw And the mounting angle is obtained by the following formulas (1), (2), (3), (4), and (5).

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
When ΔT> 0,
{(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
<{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
When ΔT <0,
-{(Screw outer diameter-Thread root diameter) / 2} <ΔT
<-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
However, D1 ≠ 0, ΔT ≠ 0, and n is the number of strips. The present invention is an invention for manufacturing a worm screw, and has the same effect as the first aspect.

That is, in the screw manufacturing method of the present invention, for example, when the workpiece and the cutter member are rotated in order to manufacture a worm screw whose lead angle is designed to satisfy the formula (X), As shown in Tables 4 and 5 of the fifth embodiment, there are effects such that the insert is less likely to interfere with the worm screw.

In particular, in the case of a worm screw in which the difference between the valley diameter and the outer diameter is large and the thread shape (cross-sectional shape perpendicular to the direction in which the screws are continuous) is special, the screw manufacturing method of the present invention is used. Thus, the processing time can be shortened while maintaining the processing accuracy.

-Furthermore, the 3rd aspect of this invention can arrange | position several inserts radially, and can hold | maintain and rotate the cyclic | annular cutter member which can be rotated centering | focusing on a rotating shaft, and the workpiece | work for forming a metric screw. In the screw manufacturing method for manufacturing the metric screw by inclining the cutter member with respect to the axial center of the workpiece by a predetermined angle (attachment angle), the lead angle of the metric screw and the attachment When the angle is different, the mounting angle is obtained by the following formulas (1), (2), and (3).

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
However, D1 ≠ 0, ΔT ≠ 0, and n is the number of strips. The present invention is an invention for manufacturing a metric screw, and has the same effect as the first aspect.

That is, in the screw manufacturing method of the present invention, for example, when the workpiece and the cutter member are rotated to manufacture a meter whose lead angle is designed to satisfy the formula (X), As shown in Tables 7 to 12 of the eleventh embodiment, there are effects such that the insert hardly interferes with the metric screw.

Further, as will be apparent from the embodiments described later, when the lead angle in the design drawing of the metric screw is less than 7 °, it cannot be said that there is much interference both at the entrance and exit even if the fluctuation is 0%. Depending on the level, there is a possibility of passing. However, if the angle exceeds 7 °, if the fluctuation is 0%, interference increases both when entering and leaving, so the mounting angle should be as in the above formulas (1), (2), and (3). Is preferred.

-Moreover, in the 4th aspect of this invention, it can set like following formula (6), (7).
When ΔT> 0,
{(Screw outer diameter-Screw valley diameter) / 2} × 0.6 ≦ ΔT
≦ {(Outer diameter of screw−Diameter of screw valley) / 2} (6)
When ΔT <0,
-{(Screw outer diameter-Thread valley diameter) / 2} ≤ΔT
≦-{(Screw outer diameter-Thread valley diameter) / 2} × 0.6 (7)
By setting in this way, as will be apparent from Tables 1 to 12, which will be described later, it is possible to further reduce interference between the curve curve of the screw and the movement path of the insert.

-Furthermore, in 5th aspect of this invention, said D1 can be made into the outer diameter of a screw, or the diameter of the trough of a screw.
By setting in this way, as will be apparent from Tables 1 to 12, which will be described later, it is possible to eliminate interference between the curve curve of the screw and the movement path of the insert.

The sixth aspect of the present invention is the annular waring cutter in which a plurality of inserts are arranged radially and rotatable about the rotation axis, with respect to the axis center of the workpiece for manufacturing a medical screw. When the Waring cutter is inclined by a predetermined angle (attachment angle) and the lead angle of the medical screw is different from the attachment angle, the following equations (1), (2), (3), (4), ( 5) is satisfied.

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
When ΔT> 0,
{(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
<{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
When ΔT <0,
-{(Screw outer diameter-Thread root diameter) / 2} <ΔT
<-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
However, D1 <> 0, [Delta] T <> 0, n is the number of threads When manufacturing a medical screw using the Waring cutter of the present invention, as in the first aspect, for example, the lead angle of the medical screw is expressed by the above formula ( Even if the design satisfies X) or a special shape unique to a medical screw, the insert is less likely to interfere with the medical screw when the workpiece and the Waring cutter are rotated.

Specifically, when the mounting angle is made smaller (shallow) than the lead angle (that is, 0 <ΔT), it is difficult to hit the side surface of the tip of the screw thread. On the other hand, if the mounting angle is larger (deeper) than the lead angle (that is, 0> ΔT), it is difficult to hit the side face of the base end of the screw thread.

Therefore, when manufacturing a medical screw using the Waring cutter of the present invention, it is desirable to suppress the interference of the movement path of the insert with the curve curve of the desired screw both when entering and entering. Screws with curved curves can be produced.

Also, in the present invention, it is possible to easily produce a small amount and a wide variety as compared with rolling. Furthermore, as compared with cutting, the machining time can be shortened, and a single workpiece can be continuously machined. Therefore, there is an advantage that it is not necessary to machine them together and machining accuracy is high.

The seventh aspect of the present invention is the annular waring cutter in which a plurality of inserts are radially arranged and rotatable about the rotation axis, with respect to the axis center of the workpiece for manufacturing the worm screw. When the Waring cutter is inclined by a predetermined angle (attachment angle) and the lead angle of the worm screw is different from the attachment angle, the following equations (1), (2), (3), (4), ( 5) is satisfied.

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
When ΔT> 0,
{(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
<{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
When ΔT <0,
-{(Screw outer diameter-Thread root diameter) / 2} <ΔT
<-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
However, D1 ≠ 0, ΔT ≠ 0, and n is the number of strips. The present invention is an invention of a Waring cutter for manufacturing a worm screw, and has the same effect as the sixth aspect.

That is, by using the Waring cutter of the present invention, for example, when the lead angle of the worm screw is designed to satisfy the above formula (X), when the workpiece or the Waring cutter is rotated, the insert becomes the worm screw. There are effects such as less interference.

Further, according to an eighth aspect of the present invention, in an annular Waring cutter in which a plurality of inserts are radially arranged and rotatable about a rotation axis, with respect to an axis center of a workpiece for manufacturing a metric screw, The Waring cutter is inclined by a predetermined angle (attachment angle), and the following formulas (1), (2), and (3) are satisfied when the lead angle of the metric screw is different from the attachment angle: To do.

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
However, D1 ≠ 0, ΔT ≠ 0, n is the number of strips. The present invention is an invention of a Waring cutter for manufacturing a metric screw, and has the same effect as the sixth aspect.

That is, by using the Waring cutter of the present invention, for example, when the lead angle of the metric screw is designed to satisfy the above formula (X), when the workpiece or the Waring cutter is rotated, the insert becomes a metric screw. There are effects such as less interference.

The ninth aspect of the present invention is that a plurality of inserts are arranged radially, and an annular waring cutter that can rotate around a rotation axis and a workpiece for manufacturing a medical screw are held coaxially. In a screw manufacturing apparatus including a main spindle to be rotated, the Waring cutter is inclined by a predetermined angle (attachment angle) with respect to the axis center of the workpiece, and a lead angle and an attachment angle of the medical screw are When they are different, the following expressions (1), (2), (3), (4), and (5) are satisfied.

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
When ΔT> 0,
{(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
<{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
When ΔT <0,
-{(Screw outer diameter-Thread root diameter) / 2} <ΔT
<-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
However, D1 <> 0, [Delta] T <> 0, and n is the number of threads When manufacturing a medical screw using the screw manufacturing apparatus of the present invention, the lead angle of the medical screw is, for example, the above formula, as in the first aspect. Even when the design satisfies (X) or a special shape peculiar to medical screws, the insert is less likely to interfere with the medical screws when the workpiece and the Waring cutter are rotated.

Specifically, when the mounting angle is made smaller (shallow) than the lead angle (that is, 0 <ΔT), it is difficult to hit the side surface of the tip of the screw thread. On the other hand, if the mounting angle is larger (deeper) than the lead angle (that is, 0> ΔT), it is difficult to hit the side face of the base end of the screw thread.

Therefore, when a medical screw is manufactured using the screw manufacturing apparatus of the present invention, it is preferable that the movement path of the insert is prevented from interfering with the curve curve of the desired screw both when entering and entering. A screw having a curve curve can be manufactured.

Also, in the present invention, it is possible to easily produce a small amount and a wide variety as compared with rolling. Furthermore, as compared with cutting, the machining time can be shortened, and a single workpiece can be continuously machined. Therefore, there is an advantage that it is not necessary to machine them together and machining accuracy is high.

The tenth aspect of the present invention is that a plurality of inserts are arranged radially, and an annular waring cutter that can rotate around a rotation axis and a workpiece for manufacturing a worm screw are held coaxially. And a main spindle for rotating the main spindle, wherein the Waring cutter is inclined by a predetermined angle (attachment angle) with respect to the axis center of the workpiece, and the lead angle and the attachment angle of the worm screw are If different
The following expressions (1), (2), (3), (4), and (5) are satisfied.

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
When ΔT> 0,
{(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
<{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
When ΔT <0,
-{(Screw outer diameter-Thread root diameter) / 2} <ΔT
<-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
However, D1 ≠ 0, ΔT ≠ 0, and n is the number of strips. The present invention is an invention of a screw manufacturing apparatus for manufacturing a worm screw, and has the same effect as the ninth aspect.

In other words, by using the screw manufacturing apparatus of the present invention, for example, when the lead angle of the worm screw is designed to satisfy the above formula (X), when the workpiece or Waring cutter is rotated, the insert becomes the worm screw. There are effects such as making it difficult to interfere with the sound.

-Furthermore, 11th aspect of this invention arrange | positions several inserts radially, hold | maintains the base for the cyclic | annular Waring cutter which can be rotated centering | focusing on a rotating shaft, and the workpiece | work for manufacturing a metric screw on the same axis | shaft. And a main spindle for rotating the main spindle, wherein the Waring cutter is inclined at a predetermined angle (attachment angle) with respect to the axial center of the workpiece, and the lead angle and the attachment angle of the metric screw are If different
The following expressions (1), (2), and (3) are satisfied.

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
However, D1 ≠ 0, ΔT ≠ 0, and n is the number of strips. The present invention is an invention of a screw manufacturing apparatus for manufacturing a metric screw, and has the same effect as the ninth aspect.

That is, by using the screw manufacturing apparatus of the present invention, for example, when the lead angle of the metric screw is designed to satisfy the above formula (X), when the workpiece or Waring cutter is rotated, the insert is metric screw. There are effects such as making it difficult to interfere with the sound.

Here, examples of the screw that is the subject of the present invention include a normal machine screw and a medical screw, but the present invention is particularly useful for manufacturing a screw having a special shape such as a medical screw. This is a suitable manufacturing method.

In addition, as a normal mechanical screw, there are various screws defined in JIS. For example, a metric screw, a worm screw, a unified screw, a trapezoidal screw, a sawtooth screw, and the like.

Medical screws are screws used in the body of humans and animals.
In the case of a medical screw, when the interference between the screw and the insert is large, the pitch is larger than that of a normal machine screw (for example, 2.0 mm or more), and the number of threads is larger than that of a single thread. For example, in the case of a double thread, a deep screw (when the difference between the outer diameter and the valley diameter is large: for example, 2.0 mm or more), and a case where the target screw has a large lead angle (for example, 15 ° or more). It is done.

It is explanatory drawing which shows the manufacturing method of the medical screw by the thread | sled Waring processing method. It is explanatory drawing which shows the Waring cutter provided with the insert. FIG. 3A is a front view showing a screw, and FIG. 3B is an explanatory view showing a part of the screw in an enlarged manner and broken. It is a perspective view which shows the insert used in 1st Embodiment. FIG. 5A is an explanatory diagram showing an interference state when the variation is −100% in the first embodiment, FIG. 5B is an explanatory diagram showing an interference state when the variation is −80%, and FIG. FIG. 5D is an explanatory diagram showing the state of interference when the variation is −40%. FIG. 5D is an explanatory diagram showing the state of interference when the variation is −40%. FIG. 6A is an explanatory diagram showing the state of interference when the variation is −20% in the first embodiment, FIG. 6B is an explanatory diagram showing the state of interference when the variation is 0%, and FIG. FIG. 6D is an explanatory diagram illustrating the state of interference when the variation is + 40%, and FIG. 6D is an explanatory diagram illustrating the state of interference when the variation is + 40%. 7A is an explanatory diagram illustrating an interference state when the variation is + 60% in the first embodiment, FIG. 7B is an explanatory diagram illustrating an interference state when the variation is + 80%, and FIG. 7C is a variation. It is explanatory drawing which shows the state of interference when making + 100%. It is a perspective view which shows the insert used in 2nd Embodiment. FIG. 9A is an explanatory diagram showing the state of interference when the variation is −100% in the second embodiment, FIG. 9B is an explanatory diagram showing the state of interference when the variation is −80%, and FIG. FIG. 9D is an explanatory diagram showing an interference state when the variation is −60%, and FIG. 9D is an explanatory diagram showing an interference state when the variation is −40%. FIG. 10A is an explanatory diagram showing the state of interference when the variation is −20% in the second embodiment, FIG. 10B is an explanatory diagram showing the state of interference when the variation is 0%, and FIG. FIG. 10D is an explanatory diagram illustrating the state of interference when the variation is + 40%, and FIG. 10D is an explanatory diagram illustrating the state of interference when the variation is + 40%. 11A is an explanatory diagram illustrating an interference state when the variation is + 60% in the second embodiment, FIG. 11B is an explanatory diagram illustrating an interference state when the variation is + 80%, and FIG. 11C is a variation. It is explanatory drawing which shows the state of interference when making + 100%. It is sectional drawing which shows the cross section along the central axis of the medical screw in 3rd Embodiment. FIG. 13A is an explanatory diagram illustrating an interference state when the variation is + 100% in the third embodiment, FIG. 13B is an explanatory diagram illustrating an interference state when the variation is + 60%, and FIG. 13C is a variation. FIG. 13D is an explanatory diagram showing the state of interference when the variation is + 0%. FIG. 14A is an explanatory view showing a worm screw in the fourth embodiment, and FIG. 14B is a cross-sectional view showing a cross section along the central axis of the worm screw. 15A is an explanatory diagram illustrating an interference state when the variation is + 100% in the fourth embodiment, FIG. 15B is an explanatory diagram illustrating an interference state when the variation is + 60%, and FIG. 15C is a variation. FIG. 15D is an explanatory diagram showing the state of interference when the variation is + 0%. It is sectional drawing which shows the cross section along the central axis of the worm screw in 5th Embodiment. FIG. 17A is an explanatory diagram illustrating an interference state when the variation is + 100% in the fifth embodiment, FIG. 17B is an explanatory diagram illustrating an interference state when the variation is + 60%, and FIG. 17C is a variation. FIG. 17D is an explanatory diagram showing the state of interference when the variation is + 0%. It is sectional drawing which shows the cross section along the central axis of the metric screw in 6th Embodiment. FIG. 19A is an explanatory diagram showing the state of interference when the variation is + 100% in the sixth embodiment (pitch 0.8), and FIG. 19B is an explanation showing the state of interference when the variation is + 0%. FIG. 19C is an explanatory diagram showing the state of interference when the variation is + 100% in the seventh embodiment (pitch 1.0), and FIG. 19D is the state of interference when the variation is + 0%. It is explanatory drawing shown. FIG. 20A is an explanatory diagram illustrating an interference state when the variation is set to + 100% in the eighth embodiment (pitch 1.25), and FIG. 20B is an explanatory diagram illustrating an interference state when the variation is set to + 0%. FIG. 20C is an explanatory diagram showing the state of interference when the variation is + 100% in the ninth embodiment (pitch 1.5), and FIG. 20D is the state of interference when the variation is + 0%. It is explanatory drawing shown. FIG. 21A is an explanatory diagram showing the state of interference when the variation is + 100% in the tenth embodiment (pitch 1.75), and FIG. 21B is an explanation showing the state of interference when the variation is + 0%. FIG. FIG. 22A is an explanatory diagram showing the state of interference when the variation is + 100% in the eleventh embodiment (pitch 2.0), and FIG. 22B is an explanation showing the state of interference when the variation is + 60%. FIG. 22C is an explanatory diagram illustrating an interference state when the variation is + 40%, and FIG. 22D is an explanatory diagram illustrating an interference state when the variation is + 0%. It is explanatory drawing which shows the problem of a prior art.

DESCRIPTION OF SYMBOLS 1, 31, 35, 41, 51, 53, 61 ... Screw 3 ... Work 5 ... Screw part 7 ... Main spindle 9 ... Waring cutter 10 ... Screw manufacturing apparatus 11 ... Cutter head 13, 21 ... Insert 17 ... Through-hole

Embodiments of the present invention will be described below with reference to the drawings.
[First Embodiment]
a) First, an outline of a method for manufacturing a medical screw by the thread whirling method will be described.

As shown in FIG. 1, in the thread whirling processing method according to the present embodiment, a threaded portion 5 is provided on the surface of a bar material (work) 3 that becomes a medical screw (hereinafter sometimes simply referred to as a screw) 1. In order to form, a main spindle 7 that rotates while holding the base of the work 3 coaxially, and a Waring cutter 9 that is arranged and rotated at an attachment angle β (°) with respect to the axial direction of the work 3 are used.

The Waring cutter 9 is an annular device that is rotated by a tool spindle (not shown). As shown in FIG. 2, a plurality of inserts 13 such as nine are arranged radially on the annular cutter head 11. is there.

Note that each insert 13 is fixed to the cutter head 11 by a fixing screw 15. An apparatus that includes the main spindle 7 and the Waring cutter 9 and manufactures the screw 1 by a thread warping method is referred to as a screw manufacturing apparatus 10.

Then, for example, when the screw 1 as shown in FIGS. 3A and 3B is manufactured by thread whirling, the following procedure is performed.
First, as shown in FIG. 1, a rod-shaped workpiece 3 is inserted into the rotation center of the main spindle 7.

Next, the workpiece 3 is inserted into the central through-hole 17 of the Waring cutter 9 and the Waring cutter 9 is inclined by a predetermined angle (attachment angle β) with respect to the central axis of the workpiece 3.
In this state, the work 3 is rotated in a predetermined direction (A direction in FIGS. 1 and 2) while moving in the axial direction (upward in FIG. 1) at a predetermined speed, and the Waring cutter 9 is rotated along with the rotation of the work 3 Screws are produced by a plurality of inserts 13 by rotating in the same direction at a rotational speed greater than the speed.

Specifically, as shown in FIG. 2, the rotation center of the Waring cutter 9 and the axis center of the workpiece 3 are arranged so that the workpiece 3 and the insert 13 are in contact (the axis center of the workpiece 3 is directed upward in the figure). Then, when the Waring cutter 9 rotates, the thread portion 5 is formed by the inserts 13 that sequentially contact the workpiece 3.

The medical screw 1 manufactured in the present embodiment is a single thread, and here, in order to produce a single thread, an insert 13 having a single cutting portion 19 as shown in FIG. 4 is used. . The shape of the insert 13 is a parallelogram shape, but a shape such as a rhombus or a triangle can also be used. A more detailed shape is determined corresponding to the shape of the screw to be manufactured.

b) Next, a method for setting the attachment angle β will be described.
The mounting angle β is determined by the shape of the screw 1 to be manufactured.
Therefore, first, as shown in FIGS. 3A and 3B, a numerical value specifying the shape of the screw 1 is read from the drawing of the screw 1 to be manufactured (here, a single thread screw).

For example, as typical data for specifying the shape of the screw 1, the following data can be given, but in addition to this, data for specifying the three-dimensional surface shape (curve) of the screw portion 5 is given. It is done. Here, numerical data of the screw 1 produced by the insert 13 is described.

Total axial length of screw: 50.0mm
Axial length of screw part: 30.0mm
Screw outer diameter: φ6.0mm
Screw valley diameter: φ4.0mm
Pitch: 5.0mm
Thread lead angle: 17.66 °
The mounting angle β and the lead angle of the screw 1 are different. That is, D1 in the formula (1) is different from the effective diameter in the formula (X).

c) Next, a specific example of a method for manufacturing the screw 1 using thread whirling will be described.
Here, the case where the screw 1 having the above-described dimensions is manufactured will be described.

As shown in FIG. 1, the work 3 is attached and fixed to the rotation center of the main spindle 7, the work 3 is inserted into the central through-hole 17 of the Waring cutter 9, and the Waring is performed with respect to the central axis of the work 3. The cutter 9 is tilted by a mounting angle β.

The mounting angle β is calculated using the following formulas (1), (2), (3), (4), (5). Here, the attachment angle β is an angle at which the Waring cutter 9 is tilted with respect to the axial center of the workpiece 3 in the thread whirling process.

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
When ΔT> 0,
{(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
<{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
When ΔT <0,
-{(Screw outer diameter-Thread root diameter) / 2} <ΔT
<-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
However, D1 (mm) ≠ 0, ΔT (mm) ≠ 0, n is the number of strips. As the work 3, a cylindrical rod made of a titanium alloy with a length of 2.5 m and an outer diameter of φ8.0 mm was used. .

And the screw 1 of the target shape shown by the drawing mentioned above according to the following processing conditions is produced.
Main spindle rotation speed: 10rpm
Work advance speed: 2.75mm / rev
Tool spindle rotation speed: 2000 rpm
Specifically, as shown in Table 1 below, the screw 1 is manufactured by changing the mounting angle β by changing D1, and at that time, interference (the curve curve of the screw 1 and the movement path of the insert 13 are not affected. The presence or absence of interference) was examined. Specifically, the simulation was performed by a well-known CAD, and the screw 1 was actually manufactured to check the interference state.

As CAD, three-dimensional CAD USG NX4 was used.
The results are shown in Table 1 below and FIGS. 5A to 5D, FIGS. 6A to 6D, and FIGS. 7A to 7C.

In Table 1, “Fluctuation” indicates the ratio of fluctuation of D1 from the intermediate value (D1 = 5.00: ΔT = 0) (when the maximum fluctuation width of 1.00 is 100%), “Fluctuation modification” indicates that the variation of 200% is converted to 100%, and “variation width” indicates the actual variation width from D1 = 5.00 (corresponding to the above ΔT).

In addition, in the judgment results, “◎” means “can avoid the interference when entering or exiting completely and can obtain the target screw shape”, and “○” means “completely appear”. "Although interference has not been avoided when entering, it is possible to process at a level that is not said to be a shape defect" and "△" are "inspection although there is much interference either when entering or entering. “Depending on the level, there is a possibility of passing”, and “×” indicates that “manufactured only products that are judged to have a shape defect due to a lot of interference both when entering and leaving.”

Here, the “target screw shape” is not only an ideal screw shape that follows a screw curve curve, but also a screw that interferes only with either the screw outer diameter side surface or the screw proximal side (valley side) side surface. Shape.

Further, in FIGS. 5A to 5D, FIGS. 6A to 6D and FIGS. 7A to 7C, the central white portion indicates the shape of the workpiece 3 before processing, the central left and right gray portions indicate the processed shapes, The gray part (within the ellipse frame) in the central white part indicates a place where interference occurs. In FIG. 6D and subsequent figures, ellipses are omitted.

As is clear from Table 1 and FIGS. 5A to 5D, FIGS. 6A to 6D, and FIGS. 7A to 7C, by adjusting the mounting angle β by changing D1, more specifically, mounting by increasing the variation amount of D1. It can be seen that by increasing the difference between the angle β and the lead angle (that is, by increasing the fluctuation), the shape of the curve curve of the screw 1 is changed, and the interference at the time of entering or entering can be reduced. .

Specifically, for example, as shown in FIGS. 5A to 5D and FIGS. 6A to 6B, when the fluctuation is increased, the shape of the interference portion is changed from one of the two fan shapes (see, for example, FIG. 6B) to the top and bottom. It changes like a fan shape (see FIG. 5A, for example).

Therefore, it can be seen that the screw 1 having a shape with little (or no) interference when coming out or entering is obtained.
Further, as apparent from comparison between FIGS. 5A to 5D and FIG. 6A, the larger the variation of the variation −20% −, the more the interference on the screw base side (valley side) can be reduced (the gray portion of the triangle). Is smaller). Similarly, when FIG. 6C is compared with FIG. 6D and FIGS. 7A to 7C, the interference of the screw outer diameter side surface can be reduced (the gray portion of the triangle becomes smaller) as the variation of + is larger than the variation + 20%. I understand.

Further, as is clear from FIG. 6B (variation 0%), when D1 is (screw root diameter + screw outer diameter) / 2 (that is, ΔT = 0), interference occurs on the screw outer diameter side surface. Since it occurs on both of the screw base end side (valley side) side surface, it becomes a problem when the manufactured screw is used. In other words, if interference occurs on both the screw outer diameter side surface and the screw base end side (valley side) side surface, it is difficult to tighten the screw with high accuracy, and further, the screw may become loose. Become.

e) Thus, in this embodiment, the screw 1 having a shape in which interference between the insert 13 and the curved curve of the screw 1 at the time of entering or entering is reduced by setting the attachment angle β and the lead angle to different values. Can be suitably obtained. Therefore, interference does not occur on both the screw outer diameter side surface and the screw base end side (valley side) side surface, so that there is no problem in using the manufactured screw 1.

That is, in this embodiment, since interference can be prevented from occurring on both sides of the screw outer diameter side surface and the screw base end side (valley side) side surface, there is no hindrance when tightening with the manufactured screw 1. The screw 1 can be rotated.

Specifically, as is clear from Tables 1 and 2, the following setting is made to further reduce interference between the curve curve of the screw 1 and the movement path of the insert 13 when entering or leaving. Can do.

When ΔT> 0,
{(Screw outer diameter-Screw valley diameter) / 2} × 0.6 ≦ ΔT
≦ {(Outer diameter of screw−Diameter of screw valley) / 2}
When ΔT <0,
-{(Screw outer diameter-Thread valley diameter) / 2} ≤ΔT
≦-{(Screw outer diameter-Screw valley diameter) / 2} × 0.6
The above (screw outer diameter−screw valley diameter) indicates the maximum fluctuation range. For example, when the fluctuation is + 60% (variation modification = + 30%), ΔT = {(screw outer diameter -Screw valley diameter) x 0.3}.

In particular, by setting D1 when calculating the mounting angle β to be the outer diameter of the screw (variation + 100%) or the diameter of the thread valley (variation −100%), the curve of the insert 13 and the screw 1 curve can be obtained. When you enter, there is no interference on either side.

Moreover, even if it is the screw 1 of a special shape like a medical screw, there exists an advantage that the screw 1 can be produced by the process of 1 time instead of the process in multiple passes.
[Second Embodiment]
Next, the second embodiment will be described, but the description of the same content as the first embodiment will be omitted.

The medical screw manufactured in the present embodiment is a double thread, and as shown in FIG. 8, the insert 21 used in the thread warping method for manufacturing the medical screw has two cutting portions 23 and 25. have.

In the present embodiment, typical data for specifying the shape of the screw includes the following data.
Total length in the axial direction of the screw: 50 mm
Axial length of screw part: 30mm
Screw outer diameter: φ4.0mm
Screw valley diameter: φ2.4mm
Pitch: 3.42mm
Thread lead angle: 18.79 °
The attachment angle β is calculated using the equations (1), (2), (3), (4), and (5) in the first embodiment.

Specifically, as shown in Table 2 below, screws were produced by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 2 below and FIGS. 9A to 9D, FIGS. 10A to 10D, and FIGS. 11A to 11C.

The meanings of the words in Table 2 and the meanings of the colors (shades) in FIGS. 9A to 9D, FIGS. 10A to 10D, and FIGS. 11A to 11C are the same as those in the first embodiment.

As is apparent from Table 2 and FIGS. 9A to 9D, FIGS. 10A to 10D, and FIGS. 11A to 11C, as in the first embodiment, by adjusting the mounting angle β by changing D1, It turns out that the interference at the time of entering can be made small.

Therefore, in this embodiment, the same effect as the first embodiment is obtained.
In addition, the double-threaded insert 21 has a blade surface ratio in the width direction compared to the height direction compared to the single-thread threaded insert in order to form two thread portions at a time. Therefore, since the insert 21 and the screw portion are likely to interfere with each other, it is not easy to form a desired screw thread. However, according to the manufacturing method of this embodiment, a screw having a desired shape can be easily manufactured. it can.

Furthermore, there is an advantage that a double thread can be manufactured by a single process rather than by a plurality of passes.
[Third Embodiment]
Next, a third embodiment will be described, but a description of the same contents as those of the second embodiment will be omitted.

The screw manufactured in this embodiment is a medical screw 31 having two threads as shown in FIG. Moreover, although not shown in figure, the insert used for the thread-waring processing method which manufactures this medical screw 31 has the shape of two cutting parts. The unit of length in FIG. 12 is mm.

In the present embodiment, typical data for specifying the shape of the screw includes the following data.
Total axial length of screw: 30mm
Axial length of screw part: 20mm
Screw outer diameter: φ5.5mm
Screw valley diameter: φ4.0mm
Intermediate value of screw: φ4.75mm
Pitch: 5.35mm
Thread lead angle: 19.72 °
The attachment angle β is calculated using the equations (1), (2), (3), (4), and (5) in the first embodiment.

Specifically, as shown in Table 3 below, a screw was produced by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 3 below and FIGS. 13A to 13D.

The meanings of the words in Table 13 and the meanings of the colors (shades) in FIGS. 13A to 13D are the same as those in the first embodiment.

As is clear from Table 13 and FIGS. 13A to 13D, as in the second embodiment, by adjusting D1 and adjusting the mounting angle β, it is possible to reduce interference when entering or leaving. I understand.

Therefore, in this embodiment, the same effect as the second embodiment is obtained. Thus, the effect of the present invention can be obtained regardless of the design of the outer diameter of the screw, the diameter of the valley, and the like.
[Fourth Embodiment]
Next, the fourth embodiment will be described, but the description of the same contents as the first embodiment will be omitted.

The screw manufactured in this embodiment is a worm screw (JIS B 1723/3) 35 having two threads as shown in FIGS. 14A and 14B. Further, although not shown, the insert used in the thread warping method for manufacturing the worm screw 35 has two cutting portions.

In the present embodiment, typical data for specifying the shape of the screw includes the following data. Note that the unit of length in FIG. 14B is mm.
Total length in the axial direction of the screw: 11 mm
Axial length of screw part: 10mm
Screw outer diameter: φ6mm
Intermediate value of screw: φ5.125mm
Screw valley diameter: φ4.25mm
Pitch: 2.872mm
Thread lead angle: 10.1141 °
The attachment angle β is calculated using the equations (1), (2), (3), (4), and (5) in the first embodiment.

Specifically, as shown in Table 4 below, a screw was produced by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 4 below and FIGS. 15A to 15D.

The meanings of the words in Table 4 and the meanings of the colors (shades) in FIGS. 15A to 15D are the same as those in the first embodiment.

As is clear from Table 4 and FIGS. 15A to 15D, as in the first embodiment, by adjusting the mounting angle β by changing D1, interference at the time of entering or exiting can be reduced. I understand.

Therefore, in the present embodiment, the same effect as that of the first embodiment can be achieved even with a general two-stage worm screw 35.
[Fifth Embodiment]
Next, the fifth embodiment will be described, but the description of the same contents as the first embodiment will be omitted.

The screw manufactured in the present embodiment is a worm screw (JIS B 1723/3) 41 having three threads as shown in FIG. Although not shown, the insert used in the thread warping method for manufacturing the worm screw 41 has a three-cut shape at the cutting portion.

In the present embodiment, typical data for specifying the shape of the screw includes the following data. Note that the unit of length in FIG. 16 is mm.
Total axial length of screw: 12mm
Axial length of screw part: 12mm
Screw outer diameter: φ7mm
Intermediate value of screw: φ6.0000mm
Screw valley diameter: φ5.000mm
Pitch: 4.867mm
Thread lead angle: 14 ° 28'39 "
The attachment angle β is calculated using the equations (1), (2), (3), (4), and (5) in the first embodiment.

Specifically, as shown in Table 5 below, a screw was produced by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 5 below and FIGS. 17A to 17D.

Note that the meanings of the words in Table 5 and the meanings of the colors (shades) in FIGS. 17A to 17D are the same as those in the first embodiment.

As is clear from Table 5 and FIGS. 17A to 17D, as in the first embodiment, by adjusting the mounting angle β by changing D1, interference at the time of entering or exiting can be reduced. I understand.

Therefore, in the present embodiment, the same effect as that of the first embodiment can be obtained even with a general three-stage worm screw 41.
[Sixth Embodiment]
Next, although the sixth embodiment will be described, description of the same contents as those of the first embodiment will be omitted.

The screws manufactured in this embodiment are general metric screws 51 and 53 having one thread as shown in FIG.
In addition, 51 is a male screw, 53 is a female screw, and in these metric screws 51 and 53, for example, when the outer diameter of the screw is φ5 mm, the pitch (p), the height of the peak (H), etc. The relationship is defined as shown in Table 6 below.

Moreover, although not shown in figure, the insert used for the thread-waring processing method which manufactures this metric screw 51 and 53 has the shape of one mountain of a cutting part.

In this embodiment, typical data for specifying the shape of a screw (for example, a metric screw 51 which is a male screw) includes the following data.
Total axial length of screw: 15mm
Axial length of screw part: 10mm
Screw outer diameter: φ5mm
Intermediate value of screw: φ4.567mm
Screw valley diameter: φ4.134mm
Pitch: 0.8mm
Thread lead angle: 3.19 °
The attachment angle β is calculated using the following formulas (1), (2), and (3).

Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
Specifically, as shown in Table 7 below, screws were manufactured by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 7 below and FIGS. 19A and 19B.

The meanings of the words in Table 7 and the meanings of the colors (shades) in FIGS. 19A and 19B are the same as those in the first embodiment.

As is clear from Table 7 and FIGS. 19A and 19B, as in the first embodiment, by adjusting D1 and adjusting the mounting angle β, it is possible to reduce interference when entering or leaving. I understand.

Therefore, in this embodiment, even in the general metric screw 51, by setting the attachment angle β and the lead angle to different values, interference between the insert and the curve curve of the screw 51 is reduced. The screw 51 having a shape can be suitably obtained. Therefore, interference does not occur on both the screw outer diameter side surface and the screw base end side (valley side) side surface, so that there is no problem in using the manufactured screw 51. That is, in this embodiment, since interference can be prevented from occurring on both sides of the screw outer diameter side surface and the screw proximal side (valley side) side surface, there is no problem when tightening with the manufactured screw 51 and the like. The screw 51 can be rotated.
[Seventh Embodiment]
Next, the seventh embodiment will be described, but the description of the same contents as the sixth embodiment will be omitted.

The screw manufactured in this embodiment is a common metric screw (male screw) having a single thread, not shown, as in the sixth embodiment, and the outer diameter is particularly the same as 5 mm. However, the pitch is as large as 1.0 mm.

Moreover, although not shown in figure, the insert used for the thread-waring processing method which manufactures this metric thread has the shape of one cutting part.
In this embodiment, typical data for specifying the shape of the metric screw includes the following data.

Total axial length of screw: 15mm
Axial length of screw part: 10mm
Screw outer diameter: φ5mm
Intermediate value of screw: φ4.459mm
Screw valley diameter: φ3.917mm
Pitch: 1.0mm
Thread lead angle: 4.08 °
The attachment angle β is calculated using the equations (1), (2), and (3) in the sixth embodiment.

Specifically, as shown in Table 8 below, screws were manufactured by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 8 below and FIGS. 19C and 19D.

The meanings of the words in Table 8 and the meanings of the colors (shades) in FIGS. 19C and 19D are the same as in the sixth embodiment.

As is clear from Table 8 and FIGS. 19C and 19D, as in the case of the sixth embodiment, by adjusting the mounting angle β by changing D1, interference at the time of entering or exiting can be reduced. I understand.

Therefore, in the present embodiment, the same effects as in the sixth embodiment are obtained.
[Eighth Embodiment]
Next, the eighth embodiment will be described, but the description of the same contents as the sixth embodiment will be omitted.

The screw manufactured in this embodiment is a common metric screw (male screw) having a single thread, not shown, as in the sixth embodiment, and the outer diameter is particularly the same as 5 mm. However, the pitch is as large as 1.25 mm.

Moreover, although not shown in figure, the insert used for the thread-waring processing method which manufactures this metric thread has the shape of one cutting part.
In this embodiment, typical data for specifying the shape of the metric screw includes the following data.

Total axial length of screw: 15mm
Axial length of screw part: 10mm
Screw outer diameter: φ5mm
Intermediate value of screw: φ4.323mm
Screw valley diameter: φ3.647mm
Pitch: 1.25mm
Thread lead angle: 5.26 °
The attachment angle β is calculated using the equations (1), (2), and (3) in the sixth embodiment.

Specifically, as shown in Table 9 below, a screw was produced by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 9 below and FIGS. 20A and 20B.

The meanings of the words in Table 9 and the meanings of the colors (shades) in FIGS. 20A and 20B are the same as those in the sixth embodiment.

As is clear from Table 9 and FIGS. 20A and 20B, as in the case of the sixth embodiment, by adjusting the mounting angle β by changing D1, the interference at the time of entering or exiting can be reduced. I understand.

Therefore, in the present embodiment, the same effects as in the sixth embodiment are obtained.
[Ninth Embodiment]
Next, a ninth embodiment will be described, but a description of the same contents as in the sixth embodiment will be omitted.

The screw manufactured in this embodiment is a common metric screw (male screw) having a single thread, not shown, as in the sixth embodiment, and the outer diameter is particularly the same as 5 mm. However, the pitch is as large as 1.5 mm.

Moreover, although not shown in figure, the insert used for the thread-waring processing method which manufactures this metric thread has the shape of one cutting part.
In this embodiment, typical data for specifying the shape of the metric screw includes the following data.

Total axial length of screw: 15mm
Axial length of screw part: 10mm
Screw outer diameter: φ5mm
Intermediate value of screw: φ 4.188mm
Screw valley diameter: φ3.376mm
Pitch: 1.5mm
Thread lead angle: 6.5 °
The attachment angle β is calculated using the equations (1), (2), and (3) in the sixth embodiment.

Specifically, as shown in Table 10 below, a screw was produced by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 10 below and FIGS. 20C and 20D.

The meanings of the words in Table 10 and the meanings of the colors (shades) in FIGS. 20C and 20D are the same as those in the first embodiment.

As is clear from Table 10 and FIGS. 20C and 20D, as in the sixth embodiment, by adjusting D1 and adjusting the mounting angle β, it is possible to reduce interference at the time of entering or leaving. I understand.

Therefore, in the present embodiment, the same effects as in the sixth embodiment are obtained.
[Tenth embodiment]
Next, the tenth embodiment will be described, but the description of the same contents as the sixth embodiment will be omitted.

The screw manufactured in this embodiment is a common metric screw (male screw) having a single thread, not shown, as in the sixth embodiment, and the outer diameter is particularly the same as 5 mm. However, the pitch is as large as 1.75 mm.

Moreover, although not shown in figure, the insert used for the thread-waring processing method which manufactures this metric thread has the shape of one cutting part.
In this embodiment, typical data for specifying the shape of the metric screw includes the following data.

Total axial length of screw: 15mm
Axial length of screw part: 10mm
Screw outer diameter: φ5mm
Intermediate value of screw: φ4.053mm
Screw valley diameter: φ 3.105mm
Pitch: 1.75mm
Thread lead angle: 7.83 °
The attachment angle β is calculated using the equations (1), (2), and (3) in the sixth embodiment.

Specifically, as shown in Table 11 below, a screw was produced by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 11 below and FIGS. 21A and 21B.

The meanings of the words in Table 11 and the meanings of the colors (shades) in FIGS. 21A and 21B are the same as those in the first embodiment.

As is clear from Table 11 and FIGS. 21A and 21B, as in the case of the sixth embodiment, by adjusting D1 and adjusting the mounting angle β, it is possible to reduce interference when entering or leaving. I understand.

Therefore, in the present embodiment, the same effects as in the sixth embodiment are obtained.
[Eleventh embodiment]
Next, the eleventh embodiment will be described, but the description of the same contents as the sixth embodiment will be omitted.

The screw manufactured in this embodiment is a common metric screw (male screw) having a single thread, not shown, as in the sixth embodiment, and the outer diameter is particularly the same as 5 mm. However, the pitch is as large as 2 mm.

Moreover, although not shown in figure, the insert used for the thread-waring processing method which manufactures this metric thread has the shape of one cutting part.
In this embodiment, typical data for specifying the shape of the metric screw includes the following data.

Total axial length of screw: 15mm
Axial length of screw part: 10mm
Screw outer diameter: φ5mm
Intermediate value of screw: φ3.917mm
Screw valley diameter: φ2.835mm
Pitch: 2mm
Thread lead angle: 9.23 °
The attachment angle β is calculated using the equations (1), (2), and (3) in the first embodiment.

Specifically, as shown in Table 12 below, a screw was manufactured by changing the mounting angle by changing D1, and at that time, the presence or absence of interference was examined. The results are shown in Table 12 below and FIGS. 22A to 22D.

The meanings of the words in Table 12 and the meanings of the colors (shades) in FIGS. 22A to 22D are the same as those in the first embodiment.

As is clear from Table 12 and FIGS. 22A to 22D, as in the case of the sixth embodiment, by adjusting D1 and adjusting the mounting angle β, it is possible to reduce interference at the time of going out or entering. I understand.

Therefore, in the present embodiment, the same effects as in the sixth embodiment are obtained.
Therefore, as is clear from the sixth to eleventh embodiments, the same effects as those of the first embodiment can be obtained even with a general metric screw.

As mentioned above, although embodiment of this invention was described, this invention is not limited to the said embodiment, As long as it belongs to the technical scope of this invention, a various form can be taken.

Claims (11)

1. A plurality of inserts arranged radially, and an annular cutter member rotatable around a rotation axis;
   A holding part capable of holding and rotating a work for forming a medical screw; and
   Use
   In the screw manufacturing method for manufacturing the medical screw by inclining the cutter member with respect to the axial center of the workpiece by a predetermined angle (attachment angle),
   When the lead angle of the medical screw and the mounting angle are different,
   The screw manufacturing method, wherein the mounting angle is obtained by the following formulas (1), (2), (3), (4), and (5).
   Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
   D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
   Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
   When ΔT> 0,
   {(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
   <{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
   When ΔT <0,
   -{(Screw outer diameter-Thread root diameter) / 2} <ΔT
   <-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
   However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes
2. A plurality of inserts arranged radially, and an annular cutter member rotatable around a rotation axis;
   A holding part which can hold and rotate a work for forming a worm screw; and
   Use
   In the screw manufacturing method for manufacturing the worm screw by inclining the cutter member with respect to the axial center of the workpiece by a predetermined angle (mounting angle),
   When the lead angle of the worm screw and the mounting angle are different,
   The screw manufacturing method, wherein the mounting angle is obtained by the following formulas (1), (2), (3), (4), and (5).
   Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
   D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
   Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
   When ΔT> 0,
   {(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
   <{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
   When ΔT <0,
   -{(Screw outer diameter-Thread root diameter) / 2} <ΔT
   <-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
   However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes
3. A plurality of inserts arranged radially, and an annular cutter member rotatable around a rotation axis;
   A holding part which can hold and rotate a work for forming a metric screw; and
   Use
   In the screw manufacturing method for manufacturing the metric screw by inclining the cutter member with respect to the axial center of the workpiece by a predetermined angle (mounting angle),
   When the lead angle of the metric screw is different from the mounting angle,
   The screw manufacturing method, wherein the mounting angle is obtained by the following formulas (1), (2), and (3).
   Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
   D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
   Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
   However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes
4. The method for manufacturing a screw according to any one of claims 1 to 3, wherein the ΔT is set in a range of the following formulas (6) and (7).
   When ΔT> 0,
   {(Screw outer diameter-Screw valley diameter) / 2} × 0.6 ≦ ΔT
   ≦ {(Outer diameter of screw−Diameter of screw valley) / 2} (6)
   When ΔT <0,
   -{(Screw outer diameter-Thread valley diameter) / 2} ≤ΔT
   ≦-{(Screw outer diameter-Thread valley diameter) / 2} × 0.6 (7)
5. The method for manufacturing a screw according to any one of claims 1 to 4, wherein the D1 is an outer diameter of a screw or a diameter of a valley of the screw.
6. In an annular waring cutter that is arranged radially with a plurality of inserts and is rotatable about a rotation axis,
   Inclining the Waring cutter by a predetermined angle (mounting angle) with respect to the axial center of a workpiece for manufacturing a medical screw,
   A Waring cutter characterized by satisfying the following formulas (1), (2), (3), (4), and (5) when the lead angle and the mounting angle of the medical screw are different.
   Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
   D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
   Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
   When ΔT> 0,
   {(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
   <{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
   When ΔT <0,
   -{(Screw outer diameter-Thread root diameter) / 2} <ΔT
   <-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
   However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes
7. In an annular waring cutter that is arranged radially with a plurality of inserts and is rotatable about a rotation axis,
   Inclining the Waring cutter by a predetermined angle (attachment angle) with respect to the axis center of the workpiece for manufacturing the worm screw,
   A Waring cutter that satisfies the following expressions (1), (2), (3), (4), and (5) when the lead angle and the mounting angle of the worm screw are different.
   Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
   D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
   Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
   When ΔT> 0,
   {(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
   <{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
   When ΔT <0,
   -{(Screw outer diameter-Thread root diameter) / 2} <ΔT
   <-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
   However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes
8. In an annular waring cutter that is arranged radially with a plurality of inserts and is rotatable about a rotation axis,
   Inclining the Waring cutter by a predetermined angle (mounting angle) with respect to the axis center of the workpiece for manufacturing the metric screw,
   When the lead angle of the metric screw is different from the mounting angle,
   A Waring cutter characterized by satisfying the following expressions (1), (2), and (3).
   Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
   D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
   Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
   However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes
9. A plurality of inserts arranged radially, and an annular waring cutter that can rotate around a rotation axis;
   A main spindle for rotating a work for manufacturing a medical screw while holding the base coaxial;
   In a screw manufacturing apparatus comprising:
   Inclining the Waring cutter by a predetermined angle (attachment angle) with respect to the axis center of the workpiece,
   When the lead angle of the medical screw and the mounting angle are different,
   The screw manufacturing apparatus characterized by satisfy | filling following formula | equation (1), (2), (3), (4), (5).
   Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
   D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
   Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
   When ΔT> 0,
   {(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
   <{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
   When ΔT <0,
   -{(Screw outer diameter-Thread root diameter) / 2} <ΔT
   <-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
   However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes
10. A plurality of inserts arranged radially, and an annular waring cutter that can rotate around a rotation axis;
    A main spindle that rotates the work for manufacturing the worm screw while holding the base coaxially;
    In a screw manufacturing apparatus comprising:
    Inclining the Waring cutter by a predetermined angle (attachment angle) with respect to the axis center of the workpiece,
    When the lead angle of the worm screw and the mounting angle are different,
    The screw manufacturing apparatus characterized by satisfy | filling following formula | equation (1), (2), (3), (4), (5).
    Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
    D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
    Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
    When ΔT> 0,
    {(Screw outer diameter−Thread valley diameter) / 2} × 0.2 <ΔT
    <{(Screw Outer Diameter-Screw Valley Diameter) / 2} (4)
    When ΔT <0,
    -{(Screw outer diameter-Thread root diameter) / 2} <ΔT
    <-{(Screw outer diameter-Thread valley diameter) / 2} × 0.2 (5)
    However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes
11. A plurality of inserts arranged radially, and an annular waring cutter that can rotate around a rotation axis;
    A main spindle that rotates the workpiece for manufacturing the metric screw while holding the base coaxially;
    In a screw manufacturing apparatus comprising:
    Inclining the Waring cutter by a predetermined angle (attachment angle) with respect to the axis center of the workpiece,
    When the lead angle of the metric screw is different from the mounting angle,
    The screw manufacturing apparatus characterized by satisfy | filling the following formula | equation (1), (2), (3).
    Mounting angle = tan ⁻¹ {n × pitch / (π × D1)} (1)
    D1 = {(screw root diameter + screw outer diameter) / 2} + ΔT (2)
    Screw valley diameter ≦ D1 ≦ Thread outer diameter (3)
    However, D1 ≠ 0, ΔT ≠ 0, n is the number of stripes

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