JP2005088066A - Enlarge-working method for shaft - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an enlarged part having wider width and larger diameter than these of the enlarged part formable in the conventional method and to reduce the compression pressure acted to a shaft material. <P>SOLUTION: In an enlarge-working method for shaft, with which a work is held with one pair of holding parts separated at a prescribed interval and at least the compression-pressure and the bending to the work between the holding parts and the rotation around the axis, are added to form the desirable enlarged part at the optional position in the work, this enlarge-working method has the peculiarity, in which the formation is applied while reducing the deformation resistance of the work by heating a part of the work at least between both holding parts. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a shaft enlargement processing method in which an enlarged portion having a diameter larger than a material diameter is integrally formed at an intermediate portion of a linear shaft material.

  Conventionally, when an enlarged portion is provided in the middle part of the shaft material, a shaft material having a diameter larger than the diameter of the shaft material is used as a material, or a method of cutting into a shape having a desired enlarged portion, or another part is used as the shaft material. The method of welding was taken. However, in the case of the former, not only the cutting work is troublesome but also wasteful in terms of materials, which is uneconomical.Further, it is difficult to cut out the enlarged portion in the middle part of a long object. there were. In the latter case, there is a problem of being affected by welding heat.

  In order to solve this problem, there is a method in which rotation, compression pressure, and bending are applied to the shaft material as a method of locally forming the enlarged portion in the intermediate portion of the shaft material. According to this technique, the enlarged portion can be easily formed in the intermediate portion of the shaft member, so that there is no need for conventional cutting or welding.

This conventional technique will be described in more detail. When a linear shaft member is held by a pair of holding portions spaced apart by a predetermined distance and at least one of the holding portions is rotated around the axis of the shaft member. By moving in the direction approaching the other and gradually biasing either of the rotating holders in the direction intersecting the axis, the rotating shaft is always subjected to compressive stress outside the bend. The compression force and the bending force are applied to the material, and the shaft material between both holding portions is caused to undergo plastic deformation in the diametrical direction of the shaft material. By gradually restoring the bias, the enlarged portion is formed in the intermediate portion of the shaft member.
Japanese Patent Laid-Open No. 62-45442

  However, in the above technique, when bending and rotating are applied to the shaft material, it is rotated by applying a compression pressure, and after bending to obtain a desired shape, it is bent back to stop the compression and rotation. . For this reason, there is a problem that a high compression pressure is required, and conversely, at a low pressure, the total number of rotations until a desired shape is obtained increases, which takes time. Furthermore, it is a limit to obtain an enlarged portion that is about twice the diameter of the shaft material to be molded, and applicable parts are also limited.

  The problem to be solved is to obtain an enlarged portion that is wider and larger in diameter than a conventionally-formable enlarged portion, and to reduce the compression pressure acting on the shaft.

According to the first aspect of the present invention, the workpiece is held by a pair of holding portions that are spaced apart by a predetermined distance, and at least a workpiece between the holding portions is subjected to compression pressure, bending, and rotation about an axis to be desired at any position of the workpiece. In the shaft enlargement processing method for forming the enlarged portion, the main feature is that the deformation resistance of the workpiece is reduced by heating at least a part of the workpiece between the two holding portions.
The invention of claim 2 is characterized in that the heating step of heating the workpiece is performed before the shaft enlargement processing is started.
Furthermore, the invention of claim 3 is characterized in that the heating step of heating the workpiece is performed during the shaft enlargement processing by applying bending, compression pressure and rotation to the workpiece.
According to a fourth aspect of the present invention, in the shaft enlargement processing method, the workpiece is relatively pushed out from at least one holding portion side of the workpiece held by the pair of holding portions spaced apart from each other to the other holding portion side. A shaft enlargement processing method characterized by applying a compression pressure to a workpiece between both holding portions.

In the shaft enlargement processing method for performing the heating step in the invention of claim 1, the work can be easily plastically deformed by reducing the deformation resistance of the work by heating the work and further improving the plastic deformability of the work. This is a tool for shaft enlargement processing.
For this reason, when the enlarged portion is formed by the axial enlargement processing method that has been conventionally performed at room temperature, the deformation resistance is large and the compression pressure to be applied is also large, and the apparatus itself is not large in order to apply this compression pressure. It was. However, as described above, the deformation resistance of the workpiece is remarkably reduced by adding the heating step, so that the enlarged portion can be formed by applying a slight compression pressure. Further, the improved plastic deformability has the advantage that not only the diameter of the enlarged portion can be made larger than before, but also a wide enlarged portion can be easily formed.
In the invention of claim 2, the heating step is performed before the shaft enlargement processing. Therefore, since it can process without making it a combined device of a heating device and a shaft enlargement processing device, it is convenient.
In invention of Claim 3, a heating process is added during axial enlargement processing. Therefore, not only can the temperature of the workpiece be easily controlled, but a larger enlarged portion can be formed.
In the invention of claim 4, the pair of holding portions spaced apart by a predetermined distance relatively approach each other and do not act on the workpiece between the holding portions, but at least from one holding portion side to the other holding portion side. In this way, a compression pressure is applied to the workpiece between the two holding parts. Therefore, since the shaft enlargement process can be performed without reducing the interval between the holding portions from the state where the workpiece is held, an enlarged portion wider than the conventional one can be formed.

A pair of holding portions 2 and 2 spaced apart by a predetermined distance hold a shaft material to be a workpiece W, and at least compression pressure and bending are applied to the workpiece W between both the holding portions 2 and 2 and rotation around the axis of the workpiece W is applied. Then, a convex portion is generated inside the workpiece W by bending, and the convex portion is accumulated on the entire circumference of the workpiece W by rotation. Then, by bending back and stopping the compression pressure and rotation, a desired enlarged portion can be formed at an arbitrary position of the workpiece W.
Further, a step of reducing the deformation resistance of the workpiece W by heating the workpiece W before or during the enlargement processing is added.
As described above, since the deformation resistance of the workpiece W is remarkably reduced by adding the heating step, the compression pressure is greatly reduced as compared with the compression pressure that has been conventionally applied to obtain the enlarged portion having the same shape. be able to. Furthermore, by increasing the plastic deformability of the workpiece by heating, it is possible to mold a thickened part that can be molded with a larger diameter and wider than before. Further, the compression pressure can be reduced, and the work holding force of each holding portion 2 and 2 can be suppressed. Therefore, the structure of the holding parts 2 and 2 can be simplified.

Next, a shaft enlargement processing method according to the present invention will be described with reference to the drawings.
A present Example demonstrates the case where the heating process which heats the workpiece | work W before performing a hypertrophy process is performed.

First, FIG. 4 shows changes in deformation resistance due to differences in processing temperature at the same processing rate of various steel materials. It can be seen that if the temperature is increased, the deformation resistance becomes smaller and the processing becomes easier. That is, the heating process in the present embodiment is for heating the workpiece W to be enlarged, thereby reducing the deformation resistance of the workpiece W and improving the workability of the workpiece W, and can heat the workpiece W. For example, the heating apparatus 1 used in the heating process is not particularly limited.
One typical heating device 1 is a combustion heating device. This apparatus uses various fuels and utilizes the heat generated by this combustion. Another heating device uses electricity. Among those using electricity, there are a resistance heating device and an induction heating device. In the former, a conductive material to be heated is directly energized, and the material to be heated is heated by Joule heat generated by internal resistance. The latter is a device in which a heated material is superheated from the surface by inserting the heated material into a coil connected to an alternating current, even though the coil and the heated material are not in contact. This utilizes the principle that an alternating magnetic flux generated by an alternating current penetrates the material to be heated, and as a result, an eddy current is generated and the surface of the material to be heated is heated by the Joule heat.
What is necessary is just to select and implement these various heating apparatuses 1 according to each Example.
In addition, when heated to a temperature equal to or higher than the recrystallization temperature of the workpiece W, not only the deformation resistance, that is, the load necessary for plastic deformation is reduced, but also the plastic deformability (elongation) is improved, It has features such as modification of the structure accompanying improvement of crystal structure due to crystal and improvement of mechanical properties, and it can be processed not only with compression pressure below conventional compression pressure, but also the diameter of enlarged part can be easily increased There is also an effect. Furthermore, reforming and mechanical properties can be improved.
In addition, when heated to a temperature below the recrystallization temperature, the deformation resistance and plastic deformability as described above are not seen, but the surface oxidation can be suppressed to the extent that no special post-processing is performed. Curing can also be used. Therefore, the heating temperature must be set as appropriate depending on the purpose of molding or the material of the workpiece W.

  Next, the configuration of a hypertrophy processing apparatus that performs hypertrophy processing will be described. This enlargement processing apparatus includes a pair of holding portions 2 and 2 that hold a workpiece W. The holding portions 2 and 2 are configured such that at least one holding portion 2 can approach or separate from the other holding portion 2 in a state where the workpiece W is held. A compression pressure can be applied to W. Furthermore, both holding parts 2 and 2 are configured to be able to rotate the held work W around the axis. Further, at least one holding portion 2 is configured to be able to be deflected in a direction intersecting with the axis of the other holding portion 2, and can bend the work W held by both holding portions 2 and 2. It is configured.

A processing procedure using the heating apparatus as described above will be described with reference to FIG.
First, after heating a desired portion or the whole of the workpiece W, which is a linear shaft member (see FIG. 1A), the workpiece W is held by a pair of holding portions 2 and 2 spaced apart from each other by a predetermined interval. At this time, the interval between the holding portions 2 is the distance that will not buckle when allowed to act bending and compression pressure on the workpiece W at the maximum, the interval between the initial gripping interval L ₀ (FIG. (B) see ).

And after hold | maintaining the workpiece | work W as mentioned above, a bending, rotation, and a compression pressure are made to act on the workpiece | work W between the both holding parts 2 and 2 (refer figure (c)). At this time, the compression pressure is applied by causing at least the holding part 2 on one side to approach the holding part 2 on the other side.
In this state, the compression pressure is such that the tensile force generated outside the bending of the workpiece W is canceled and no tensile force is applied, or the compressive force is applied, and the deformation resistance is remarkably lowered by heating the workpiece W. Therefore, the compression pressure applied at this time may be small. Furthermore, the bending angle may be added several degrees. If this angle is increased, the workpiece W is likely to buckle, and the workability deteriorates. Further, the rotation speed may be several rotations per minute to several hundred rotations.
When these act on the workpiece W, a convex portion is generated at a position located inside the bending of the workpiece W. At this time, a tensile force is normally generated on the outer side of the bend, but fatigue of the workpiece W is prevented by applying a compressive pressure that can cancel the tensile force. And by rotating the workpiece | work W, the said convex part is accumulated on the workpiece | work W perimeter, and a desired enlarged part is shape | molded (refer figure (d)).

Thereafter, when a desired enlarged portion is formed, bending back is performed to straighten the workpiece W (see FIG. 5E). After straightening, the compression pressure and rotation may be stopped, and the workpiece W may be taken out from the holding units 2 and 2.
If the workpiece W is taken out from the holding portions 2 and 2 in this manner, an enlarged portion having a width L ₁ (L ₀ > L ₁ ) and an enlarged portion diameter D ₁ is formed in the intermediate portion of the workpiece W having the material diameter D _0. (See FIG. (F)).

  In this way, by heating at least a desired position of the intermediate portion of the workpiece W, that is, a portion to be enlarged and formed before the shaft enlargement processing is performed, the deformation resistance of the workpiece W is reduced, and thereafter the shaft enlargement processing is performed. Therefore, since the deformation resistance is reduced, the shaft enlargement processing can be performed with a compression pressure smaller than the compression pressure when the shaft enlargement processing is conventionally performed at room temperature, and a desired enlarged portion can be formed. Since the compression pressure to be applied is small, the work holding force of the holding portions 2 and 2 may be small, and the configuration of the holding portions 2 and 2 can be simplified.

Next, a shaft enlargement processing method when a compression pressure is applied by a method different from that in the first embodiment will be described.
The shaft enlargement processing apparatus that performs this shaft enlargement processing method includes a pair of holding portions 2 and 2 similar to those in the first embodiment. Further, the holding units 2 and 2 or the processing apparatus are configured to be able to push out the workpiece W held by one holding unit 2 to the other holding unit 2 side while holding the workpiece W. As one embodiment of the present invention, one work rear end may be pushed out by a telescopic means such as a hydraulic cylinder.

A processing procedure using the heating apparatus as described above will be described with reference to FIG.
First, after heating a desired portion or the whole of the workpiece W, which is a linear shaft member (see FIG. 1A), the workpiece W is held by a pair of holding portions 2 and 2 spaced apart from each other by a predetermined interval. At this time, the interval between the holding portions 2 and 2 is set to a maximum so that it does not buckle when bending and compressive pressure are applied to the workpiece W, as in the first embodiment, and this interval is set as an initial gripping interval L ₀ . (Refer figure (b)).

And after hold | maintaining the workpiece | work W as mentioned above, a bending, rotation, and a compression pressure are made to act on the workpiece | work W between the both holding parts 2 and 2 (refer figure (c)). At this time, unlike the first embodiment, the compression pressure is applied by pushing the workpiece W from the holding part 2 on one side to the holding part 2 on the other side.
The compression pressure, bending angle, and rotation speed are the same as in the first embodiment.
When these act on the workpiece W, a convex portion is generated at a position located inside the bending of the workpiece W. At this time, a tensile force is normally generated on the outer side of the bend, but fatigue of the workpiece W is prevented by applying a compressive pressure that can cancel the tensile force. And by rotating the workpiece | work W, the said convex part is accumulated on the workpiece | work W perimeter, and a desired enlarged part is shape | molded (refer figure (d), (e), (f)).

Thereafter, if a desired enlarged portion is formed, bending back is performed to straighten the workpiece W (see FIG. (G)). After straightening, the compression pressure and rotation are stopped, and the workpiece W may be taken out from the holding portions 2 and 2 (see FIG. (F)).
If the workpiece W is taken out from the holding portions 2 and 2 in this manner, an enlarged portion having a width L ₂ (L ₀ = L ₂ ) and an enlarged portion diameter D ₂ is formed in the intermediate portion of the workpiece W having the material diameter D _0. Can do.

According to the axial enlargement processing method as described above, may be the initial gripping distance L ₀ between enlarged portion width L ₂ is obtained the same. Moreover, by extruding the workpiece W in turn kept heated somewhat in a wide range, can be also enlarged portion diameter D ₂ forming the large.

Next, a shaft enlargement processing method different from the first and second embodiments will be described.
As the shaft enlargement processing apparatus for performing this shaft enlargement processing method, the device used in Example 2 is used.

A processing procedure using the above processing apparatus will be described with reference to FIG.
First, after heating a desired portion or the whole of the workpiece W, which is a linear shaft member (see FIG. 1A), the workpiece W is held by a pair of holding portions 2 and 2 spaced apart from each other by a predetermined interval. At this time, the interval between the holding portions 2 and 2 is set to a maximum so as not to buckle when bending and compressing pressure are applied to the workpiece W as in the first and second embodiments, and this interval is the initial gripping interval L _0. (Refer to FIG. 2 (b)).

And after hold | maintaining the workpiece | work W as mentioned above, a bending, rotation, and a compression pressure are made to act on the workpiece | work W between the both holding parts 2 and 2 (refer figure (c)). At this time, unlike the first embodiment, the compression pressure is applied by pushing the workpiece W from the holding part 2 on one side to the holding part 2 on the other side.
The compression pressure, bending angle, and rotation speed are the same as in the first embodiment.
When these act on the workpiece W, a convex portion is generated at a position located inside the bending of the workpiece W. At this time, a tensile force is normally generated on the outer side of the bend, but fatigue of the workpiece W is prevented by applying a compressive pressure that can cancel the tensile force. And by rotating the workpiece | work W, the said convex part is accumulated on the workpiece | work W perimeter, and a desired enlarged part is shape | molded (refer figure (d)).
Thereafter, if the diameter of the enlarged portion is increased, the distance between the holding portions 2 and 2 is gradually increased (see FIG. (E)). At this time, even if the interval between the holding portions 2 and 2 is widened, the diameter of the enlarged portion is increased, so that the workpiece W is less likely to buckle, and the enlargement process proceeds normally to form a desired enlarged portion. it can. Then, if the desired enlarged portion can be molded, at least the holding portion 2 on one side approaches the other holding portion 2 side, and the shape of the enlarged portion is adjusted (see FIG. (F)).

Thereafter, if a desired enlarged portion is formed, bending back is performed to straighten the workpiece W (see FIG. (G)). Thereafter, the compression pressure and rotation are stopped, and the work W may be taken out from the holding parts 2 and 2 (see FIG. (H)).
If the workpiece W is taken out from the holding portions 2 and 2 in this way, an enlarged portion having a width L ₃ (L ₀ <L ₃ ) and an enlarged portion diameter D ₃ is formed in an intermediate portion of the workpiece W having the material diameter D _0. Can do.

According to the axial enlargement processing method as described above, it can be enlarged portion width L ₃ from the initial gripping interval L ₀ get large. Moreover, by extruding the workpiece W sequentially, enlarged section diameter D ₃ can also be formed larger ones.

So far, the case where the heating step is performed before the shaft enlargement processing has been described, but the heating step is performed in parallel with the shaft enlargement processing while taking a processing procedure substantially the same as that of Example 2 or Example 3. By doing so, an enlarged portion having a larger diameter and a wider width can be formed.
In this case, during shaft enlargement processing, that is, in a state where the workpiece W is held by both holding portions 2 and 2 and in a state where the workpiece W is bent and compression pressure and rotation are applied, both holding is performed using an induction heating device or the like. What is necessary is just to heat a part or all of the workpiece | work between parts.
In this way, by adding a heating step during the shaft enlargement processing, the workpiece W is supplied from at least one holding portion while reducing the deformation resistance of the workpiece W. Therefore, a processing procedure substantially similar to that of the second embodiment is performed. If it takes, a thing with a larger enlarged part diameter can be shape | molded. Moreover, if the process procedure substantially the same as Example 3 is taken, a thing with a larger enlarged part diameter or a wider enlarged part part can be easily shape | molded.

According to the shaft enlargement processing method to which such a heating process is added, unlike the case where another part is welded or manufactured by cutting, a flow of crystal structure is generated according to the contour of the enlarged portion during molding, which is forged. The enlarged portion formed with the forging line can be formed at an appropriate position in the middle of the shaft. Therefore, the material strength along the forging line of the enlarged portion is remarkable, and the actual strength as a product by this axial enlargement processing has been increased.
Therefore, it is possible to obtain an enlarged portion that is wider and has a larger diameter than before, and can be applied to various parts.

Explanatory drawing which shows a processing procedure (Example 1) Explanatory drawing which shows a processing procedure (Example 2) Explanatory drawing which shows a processing procedure (Example 3) Explanatory diagram showing the relationship between processing temperature and deformation resistance

Explanation of symbols

1 Heating device 2 Holding part W Work D ₀ Work diameter D ₁ Enlarged part diameter D ₂ Enlarged part diameter D ₃ Enlarged part diameter L ₀ Initial grip interval L ₁ Enlarged part width L ₂ Enlarged part width L ₃ Enlarged part width

Claims (4)

  A shaft that holds a workpiece with a pair of holding portions spaced apart by a predetermined distance, and forms a desired enlarged portion at an arbitrary position of the workpiece by adding compression pressure, bending, and rotation around the axis to at least the workpiece between the holding portions. In the enlargement processing method, the shaft enlargement forming method is characterized in that at least a part of the work between both holding parts is heated to reduce the deformation resistance of the work to perform the forming.   2. The shaft enlargement processing method according to claim 1, wherein the heating step of heating the workpiece is performed before the shaft enlargement processing is started.   2. The shaft enlargement processing method according to claim 1, wherein the heating step of heating the workpiece is performed during the shaft enlargement processing by applying bending, compression pressure and rotation to the workpiece.   In the shaft enlargement processing method, the pressure between the two holding parts is relatively reduced by pushing the work from at least one holding part side of the work held by a pair of holding parts spaced apart from each other to the other holding part side. A shaft enlargement processing method characterized by causing a to act.