JP7188234B2 - Cylindrical structure, manufacturing method and manufacturing apparatus for cylindrical structure - Google Patents

Description

TECHNICAL FIELD The present invention relates to a manufacturing method and manufacturing apparatus for a cylindrical structure by front-rear extrusion forging.

At present, cylindrical structures with an H-shaped cross section are used for mechanical equipment, automobiles, spacer parts, bearing sleeves, gears, etc. of chemical plants, and most of them are manufactured by cutting round bars.
If a cylindrical structure is manufactured by cutting a round bar, the material yield is low and the production takt time is extremely low. For this reason, in recent years, it has become common to press a plate material with a press to form it into a near-net shape, which is a shape close to the final product, and then perform cutting to obtain the final product shape.

As one of the methods for manufacturing such a near-net-shape tubular structure, front-rear extrusion forging is known, in which a columnar raw material is split in the front-rear direction and extruded (see Patent Document 1).

Japanese Patent Application Laid-Open No. 2006-007260

When manufacturing a cylindrical structure having a partition plate portion by the above-mentioned forward and backward extrusion forging, the tip of the material flowing in the forward and backward directions is not restrained by the mold and becomes a free end, so it is extruded. Difficult to control length. Therefore, it is difficult to obtain a desired shape, and a large amount of cutting is required in the cutting process after forging.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a manufacturing method and a manufacturing apparatus capable of forming a partition plate portion at an arbitrary location when a tubular structure having a partition plate portion is produced by front-rear extrusion forging. .

但し、Ｖ１及びＶ３は下方向を正とし、Ｖ２は上方向を正とし、Ｈ１_０及びＨ２_０はＶ２＝０で加工した場合のそれぞれのＨ１及びＨ２の実測値とする。 The present invention is a manufacturing method for manufacturing a cylindrical structure having a cylindrical portion and a partition plate portion for partitioning the interior of the cylindrical portion from a cylindrical material by front-rear extrusion forging, wherein the outer diameter of the cylindrical material and the A cylindrical upper mold and a lower mold having a predetermined diameter smaller than the outer diameter of the cylindrical material are installed inside a side mold having an annular shape with an inner diameter of at least the same size, and the upper mold and the lower mold are installed. The columnar material is arranged between the lower mold, the speed of the upper mold in the processing direction is set to a predetermined speed V1, the moving speed of the side mold along the processing direction is set to V2, and the lower mold The speed in the processing direction is a predetermined speed V3, the desired length from the center of the plate thickness of the partition plate portion to the upper end of the cylindrical structure is H1, and the desired length to the lower end is H2. , the upper mold and the lower mold are moved relatively close to each other to press the cylindrical material, and the side mold is moved at a speed of V2 represented by the following formula (1). Regarding the method.

However, V1 and V3 are positive in the downward direction, V2 is positive in the upward direction, and H10 and H20 are measured values of H1 and H2 when V2 _{= 0} .

Moreover, in the above formula (1), it is preferable to set the speed of V2 so that −0.55≦V2/(V1+V3)≦−0.45.

Moreover, it is preferable to set V3=0 in the above formula (1).

但し、Ｖ１及びＶ３は下方向を正、Ｖ２は上方向を正、Ｈ１_０及びＨ２_０はＶ２＝０で加工した場合のそれぞれのＨ１及びＨ２の実測値とする。 Further, the present invention provides a manufacturing apparatus for manufacturing a cylindrical structure having a cylindrical portion and a partition plate portion for partitioning the inside of the cylindrical portion from a cylindrical material by front-rear extrusion forging, the manufacturing apparatus comprising: a side mold that has an annular shape with an inner diameter that is at least as large as the outer diameter of the cylindrical material and is movable along the processing direction; a cylindrical upper die and a lower die having a small predetermined diameter, wherein the speed of the upper die in the processing direction is set to a predetermined speed V1, and the moving speed of the side die along the processing direction is set to V2; The speed of the lower die in the working direction is set to a predetermined speed V3, the desired length from the center of the plate thickness of the partition plate portion to the upper end of the cylindrical structure is H1, and the desired length to the lower end is H2. In this case, the present invention relates to a manufacturing apparatus that moves the upper mold and the lower mold relatively closer to each other and controls the lateral mold to move at a speed of V2 represented by the following formula (1).

However, V1 and V3 are positive in the downward direction, V2 is positive in the upward direction, and H10 and H20 are measured values of H1 and H2 when V2 _{= 0} .

Further, the present invention provides a cylindrical structure having a cylindrical portion manufactured by the manufacturing method and a partition plate portion that partitions the inside of the cylindrical portion, wherein the grain flows of the cylindrical structure are formed by the partition The plate portion is formed along the radial direction, and the cylindrical portion is formed so as to continue from the partition plate portion and extend from the inner surface to the outer surface along the upper end surface or the lower end surface. , the direction of the grain flow lines on the outer surface for the tubular structure being mostly along the radial direction.

In addition, the present invention provides a cylindrical portion manufactured by the above manufacturing method in which the speed of V2 is set to −0.55≦V2/(V1+V3)≦−0.45 and a partition plate portion that partitions the inside of the cylindrical portion. In the cylindrical structure, the grain flows of the cylindrical structure are formed along the radial direction in the partition plate portion, and in the cylindrical portion, the plate of the partition plate portion The present invention relates to a tubular structure formed vertically substantially symmetrically about a center plane of thickness.

According to the present invention, by controlling the movement speed of the container under a predetermined condition during the front-rear extrusion forging, it is possible to manufacture a cylindrical structure provided with a partition plate portion at an arbitrary location.

It is explanatory drawing of the manufacturing method which concerns on embodiment of this invention. It is explanatory drawing of the cylindrical structure obtained by the manufacturing method of this invention. FIG. 4 is an explanatory diagram of a method for obtaining a vertically symmetrical tubular structure when fixing a die; FIG. 4 is an explanatory diagram of a method for obtaining a vertically symmetrical cylindrical structure without fixing a die; 4 is a logarithmic graph showing the relationship between the shape of a tubular structure and container speed. FIG. 4 is an explanatory diagram of a method for calculating a coefficient of a container speed conditional expression; It is explanatory drawing of the manufacturing method by which a vertically symmetrical cylindrical structure is obtained. FIG. 4 is a schematic diagram for explaining the shape of grain flow lines of a vertically symmetrical cylindrical structure; 4 shows the observation results of the cross-sectional shape and grain flow lines of the tubular structure obtained in Example 1. FIG. An example of application of a vertically symmetrical cylindrical structure is shown. FIG. 4 is a diagram for explaining a cut-out shape of a test piece for measuring deformation strength; It is a schematic diagram for demonstrating the test method of deformation strength. 4 is a graph showing the results of strength test (1). It is a graph which shows the result of a strength test (2).

Preferred embodiments of the method and apparatus for manufacturing a tubular structure according to the present invention will be described below with reference to FIGS. 1 to 8. FIG.

<Embodiment>
FIG. 1 is a schematic cross-sectional view of a manufacturing apparatus 1 for explaining the manufacturing method according to this embodiment, and FIG. 2 is an explanatory diagram of a tubular structure obtained by the manufacturing method according to this embodiment.

As shown in FIG. 1, the manufacturing apparatus 1 includes a punch 10 as an upper die, a container 20 as a side die, and a die 30 as a lower die. They are arranged inside the container 20 so that their central axes are aligned.

The punch 10 has a cylindrical shape with a predetermined diameter smaller than the outer diameter of the cylindrical material 40A, which is the object to be processed, and can move up and down.

The container 20 has an annular shape with an inner diameter that matches the outer diameter of the cylindrical material 40A, and is movable up and down in the processing direction. The inner diameter of the container 20 may be slightly larger than the outer diameter of the cylindrical material 40A. preferably match the outer diameter of the

The die 30 has a cylindrical shape with a predetermined diameter smaller than the outer diameter of the cylindrical material 40A, and is movable up and down. In this embodiment, the diameter of the die 30 is configured to match the punch 10 to produce a tubular structure with a constant inner diameter.

As a raw material for the cylindrical material 40A, a special steel or stainless steel plate, a round bar material cut and swept into a disc shape, or the like can be used.

In the manufacturing method of this embodiment, the cylindrical material 40A is arranged between the punch 10 and the die 30, the punch 10 is moved at a predetermined speed V1 (positive in the downward direction), and the die 30 is moved at a predetermined speed V3 ( The downward direction is assumed to be positive), and the cylindrical material 40A is moved relatively closer to press the cylindrical material 40A. A shaped tubular structure 40B is obtained. The container speed V2 is set based on a conditional expression to be described later.

The shape of the tubular structure 40B will be described with reference to FIG.
The tubular structure 40B includes a cylindrical portion 41 and a partition plate portion 42 that partitions the interior of the cylindrical portion 41 (see FIG. 2(a)). The cross-sectional shape is H-shaped, the length from the thickness center of the partition plate portion 42 to the upper end of the tubular structure is H1, and the length to the lower end is H2 (see FIG. 2B).
According to the manufacturing method of the present invention, the height (H1+H2) of the tubular structure 40B can be obtained by setting desired H1 and H2 to obtain the tubular structure 40B in which the partition plate portion 42 is formed at an arbitrary location. can be done.

First, a method for obtaining a tubular structure 40B having an H-shaped cross-sectional shape vertically symmetrical at the center of the plate thickness by pressing the cylindrical material 40A, that is, obtaining a tubular structure 40B satisfying H1=H2. Description will be made with reference to FIGS. 3 and 4. FIG.

A case where the die 30 is fixed will be described with reference to FIG. The plate thickness of the cylindrical material 40A before press working is t ₀ (see FIG. 3(a)), and the plate thickness after press working is t (see FIG. 3(b)).
As shown in FIG. 3, X is the coordinate in the plate thickness direction (upward) of the cylindrical material 40A, and the origin of the X coordinate is the bottom of the cylindrical material 40A sandwiched between the punch 10 and the die 30 before press working. Let us consider the transition of the coordinates of the sheet thickness center before and after press working.
The coordinates of the plate thickness center of the cylindrical material 40A before press working can be expressed as X=t ₀ /2. Assuming that the movement amount of the punch 10 is X1 and the die 30 is fixed, the plate thickness t of the partition plate portion 42 after press working is t=t ₀ -X1, and the coordinates of the plate thickness center of the partition plate portion 42 are , X=t/2=(t ₀ −X1)/2.

In order for the cylindrical structure 40B after press working to be vertically symmetrical, the plate of the partition plate portion 42 is arranged so that the center coordinates in the X direction of the cylindrical portion 41 match the coordinates of the plate thickness center of the partition plate portion 42. It is necessary to process the tubular structure 40B while keeping the center line of thickness straight.
For this reason, it is considered to correct the container 20 by the movement amount X2 so that the X-direction center line of the portion that becomes the cylindrical portion 41 can follow the center line of the plate thickness of the cylindrical material 40A.
The coordinates of the center line in the X direction of the cylindrical portion 41 when the container 20 is moved by the movement amount of X2 are X=t ₀ /2+X2, which is the coordinate of the plate thickness center of the partition plate portion 42 X=( t ₀ -X1)/2. From this, X2=-(1/2)X1 is obtained. Converting the moving amounts X1 and X2 into moving speed V1=X1/s and V2=X2/s (s: time required for pressing), V2/V1 A relational expression 1 of =-0.5 is obtained.
In other words, if the relational expression 1 of V2/V1=-0.5 is satisfied, the H-shaped structure is vertically symmetrical about the center of the plate thickness without being affected by the coefficient of friction, the sizes of V1 and V2, and the material of the cylindrical material 40A. A tubular structure 40B can be obtained.

Next, the case where the die 30 is not fixed and moves at the moving speed V3 will be described with reference to FIG. The plate thickness of the cylindrical material 40A before press working is t ₀ (see FIG. 4(a)), and the plate thickness after press working is t (see FIG. 4(b)).
As shown in FIG. 4, the coordinate in the plate thickness direction (upward) of the cylindrical material 40A is X, and the bottom of the cylindrical material 40A sandwiched between the punch 10 and the die 30 before press working is the origin of the X coordinate. Let us consider the transition of the coordinates of the sheet thickness center before and after press working.
The coordinates of the plate thickness center of the cylindrical material 40A before press working can be expressed as X=t ₀ /2. Assuming that the movement amount of the punch 10 is X1 and the movement amount of the die 30 is X3, the coordinates of the plate thickness center of the partition plate portion 42 after press working are moved by X3 to 1/2 of the plate thickness t after press working. is added, X=t/2+X3 can be expressed. The plate thickness t of the partition plate portion 42 after press working is t=t ₀ -X1+X3, and the coordinates of the plate thickness center of the partition plate portion 42 are X=t/2+X3=(t ₀ -X1+X3)/2+X3. .

The coordinates of the center line in the X direction of the cylindrical portion 41 when the container 20 is moved by X2 are X=t ₀ /2+X2, which is the coordinate of the plate thickness center of the partition plate portion 42 X=(t ₀ − X1+X3)/2+X3 is sufficient. From this, X2=-(X1+X3)/2 is obtained, and moving amounts X1, X2 and X3 are changed to moving speed V1=X1/s, V2=X2/s, V3=X3/s (s: time required for pressing) , the relational expression 2 of V2/(V1+V3)=-0.5 is obtained.
In other words, if the relational expression 2 of V2/(V1+V3)=-0.5 is satisfied, the friction coefficient, the sizes of V1, V2, and V3, and the material of the cylindrical material 40A do not affect the vertical symmetry at the thickness center. can obtain the H-shaped tubular structure 40B.

Next, a method for obtaining a tubular structure 40B in which desired H1 and H2 are set and the partition plate portion 42 is formed at an arbitrary location will be described. In order to obtain a conditional expression for setting the container speed V2, the results of simulating the shape of the tubular structure 40B when the container speed V2 is changed at a predetermined punch speed V1 and a predetermined die speed V3 are shown. 1.
The punch speed was constant at V1=3, the die 30 was fixed (V3=0), and the container speed V2 was set at −33≦V2≦30. The diameter of the punch and die is 17 mm, the radius of curvature of the corners of the punch and die is 0.3 mm, the inner diameter of the container is 24 mm, the diameter of the cylindrical material 40A is 24 mm, and the plate thickness is 4.2 mm. The simulation was performed under the condition that the plate thickness of the partition plate portion 42 of the tubular structure 40B after processing 40A was 1.2 mm.

As shown in FIG. 5, it was shown that various shapes can be formed by changing the container speed V2.

In order to obtain a conditional expression for setting the container speed V2, the correlation between V2/(V1+V3) in Table 1 and H2/H1 is shown in the logarithmic graph of FIG. Although not shown in the table, FIG. 5 also shows the results of a simulation with the punch speed V1=2 and the die speed V3=-1.

According to the graph of FIG. 5, it can be seen that a straight line having a predetermined slope a and a predetermined intercept b passes through the point of H2/H1=1 when V2/(V1+V3)=-0.5.
Below, a relational expression between V2/(V1+V3) and H2/H1 is obtained, and a conditional expression for V2 is obtained from the relational expression.
Assuming that V2/(V1+V3) is x and H2/H1 is y, the slope a and the intercept b of the following formula (2) are obtained.
logy=ax+b (2)
From the graph shown in FIG. 5, it can be seen that the range of H2/H1 in which the formula (2) holds is approximately 1/7≦H2/H1≦7.
Considering a and b in formula (2), the values of H1 and H2 when press working is performed with x=0, that is, the container speed V2=0 (when the container 20 is not moved) as shown in FIG. Assuming that the values are H1 ₀ and H2 ₀ respectively, b=logH2 ₀ /H1 ₀ from Equation (2). Further, from the above, when x=V2/(V1+V3)=-0.5, y=H2/H1=1, so substituting this into equation (2) yields a=2b. From these, it can be expressed as a=2logH2 ₀ /H1 ₀ .
Since a and b in formula (2) can be represented by H2 ₀ and H1 ₀ , by measuring H1 and H2 when the container 20 is not moved, the relational expression between V2/(V1+V3) and H2/H1 can be obtained. can be done.

但し、１／７≦Ｈ２／Ｈ１≦７。 To find the conditional expression for V2, substitute x=V2/(V1+V3), y=H2/H1, a=2logH2 ₀ /H1 ₀ and b=logH2 ₀ /H1 ₀ into the equation (2) to obtain By rearranging, the following formula (1) is obtained.

However, 1/7≤H2/H1≤7.

From the above, in order to obtain the desired cylindrical structure 40B with H1 and H2 at a predetermined punch speed V1 and a predetermined die speed V3, the container speed V2 should be calculated from Equation (1).
For example, under the conditions of V1=3 and V3=0 in Table 1, when V2= ₀ , H2/H1 ₌ H20/H10=0.74. , V2=−4.95 can be calculated from the equation (1). That is, if the container 20 is moved downward at a speed of 4.95 during press working, the cylindrical structure 40B with H2/H1 of approximately 2 can be obtained.

Further, according to the formula (1), when it is desired to make the tubular structure 40B vertically symmetrical with respect to the plate thickness center plane of the partition plate portion 42, that is, when it is desired to set H1=H2, V2= It may be set to -1/2(V1+V3), which agrees with relational expression 2 described above with reference to FIG. When V2 is set such that -0.55≤V2/(V1+V3)≤-0.45 centering on V2/(V1+V3)=-0.5, a substantially vertically symmetrical cylindrical structure 40B can be obtained. . In particular, as shown in FIG. 7, when the die 30 is fixed (V3=0), V2=-1/2V1 may be set, which corresponds to the relational expression 1 described in FIG. do. If the container 20 is moved downward at a speed of 1/2V1 during press working, a vertically symmetrical tubular structure 40B can be obtained.

In the above description, the case where the die 30 is fixed has been shown, but the present invention is not limited to this. By fixing the die 30, processing can be performed using a single-pressing press device, and press processing can be performed with simple equipment compared to a double-pressing press device in which both the punch 10 and the die 30 are driven. can.

Next, the shape of the grain flow lines will be described with reference to FIG. 8, which is a schematic sectional view showing the grain flow lines formed in the tubular structure 40B manufactured by the manufacturing method of the invention. FIG. 8(a) shows a case where the tubular structure 40B has a vertically asymmetrical structure (H1≠H2) with respect to the plate thickness center plane of the partition plate portion 42, and FIG. 8(b) shows the tubular structure 40B. shows a case (H1=H2) in which the structure is vertically symmetrical with respect to the center plane of the plate thickness of the partition plate portion 42 .

When the cylindrical structure 40B is forged by the manufacturing method of the present invention using a steel round bar or steel plate manufactured by rolling as the cylindrical material 40A, as shown in FIGS. , the grain flow lines MF are formed along the shape of the tubular structure without intersecting each other and without being interrupted. More specifically, the grain flows MF are formed in the partition plate portion 42 in a direction substantially perpendicular to the plate thickness direction, i.e., along the radial direction, and in the cylindrical portion 41, continue from the partition plate portion 42. It is formed so as to reach the outer surface along the upper end surface or the lower end surface from the inner surface. The direction of the grain flows MF on the outer surface is mostly along the radial direction. Therefore, the mechanical properties of the tubular structure 40B can be improved.

As shown in FIG. 8B, when the cylindrical structure 40B has a vertically symmetrical shape, the grain flow lines MF in the cylindrical portion 41 are also substantially symmetrical about the central plane of the plate thickness of the partition plate portion 42. formed in In addition, on the center line, foreign substances accumulated when rolling a steel round bar or steel plate to obtain the cylindrical material 40A are included. The accumulated foreign matter follows the same route as the grain flow line on the center line, so it can substitute for the grain flow line. Therefore, the shape is almost symmetrical in the vertical direction, the strain distribution is also almost symmetrical in the vertical direction, and the strength is also considered to be almost symmetrical in the vertical direction. can do In addition, when heat treatment such as quenching is performed in a later step, warpage can be reduced because the strain distribution is substantially symmetrical in the vertical direction.

As described above, the shape of the grain flow in the cylindrical structure 40B manufactured by the manufacturing method of the present invention can be obtained by cutting from a processed product or plate material using a round bar or pipe manufactured using conventional technology. It is clearly different from the shape of the grain flow line in the product processed by the construction method. Therefore, by visualizing the grain flow lines in the cross section by electrolytic etching and observing the grain flow lines, it is possible to easily distinguish between those manufactured by the conventional technology and those manufactured by the present invention.

According to the manufacturing method and manufacturing apparatus 1 of the tubular structure 40B of the present embodiment described above, the following effects are obtained.

但し、Ｖ１及びＶ３は下方向を正とし、Ｖ２は上方向を正とし、Ｈ１_０及びＨ２_０はＶ２＝０で加工した場合のそれぞれのＨ１及びＨ２の実測値とする。
これにより、円筒部４１の任意の場所に仕切板部４２を設けることができるので、ニアネットシェイプ加工を行うことができ、また、後の工程で切削加工が必要な場合でも、切削量を削減することができる。 (1) A tubular structure 40B having a cylindrical portion 41 and a partition plate portion 42 for partitioning the inside of the cylindrical portion 41 is formed by forging from the cylindrical material 40A by front-rear extrusion forging to have a size at least equal to the outer diameter of the cylindrical material 40A. A cylindrical upper mold 10 and a lower mold 30 having a predetermined diameter smaller than the outer diameter of the cylindrical material 40A are installed inside the side mold 20 having an annular shape with an inner diameter of . The cylindrical material 40A is arranged between the mold 30, the speed in the processing direction of the upper mold 10 is set to a predetermined speed V1, the moving speed of the side mold 20 along the processing direction is set to V2, and the lower mold 30 When the speed in the processing direction is a predetermined speed V3, the desired length from the thickness center of the partition plate portion 42 to the upper end of the cylindrical structure 40B is H1, and the desired length to the lower end is H2, The upper mold 10 and the lower mold 30 are moved relatively close to each other to press the cylindrical material 40A, and the side mold 20 is moved at a speed of V2 represented by the following formula (1). shall be.

However, V1 and V3 are positive in the downward direction, V2 is positive in the upward direction, and H10 and H20 are measured values of H1 and H2 when V2 _{= 0} .
As a result, the partition plate portion 42 can be provided at an arbitrary location on the cylindrical portion 41, so that near-net shape processing can be performed, and even if cutting is required in a later process, the amount of cutting can be reduced. can do.

(2) In formula (1), the speed of V2 is set so that -0.55≤V2/(V1+V3)≤-0.45. As a result, the shape is almost symmetrical, the strain distribution is almost symmetrical, and the strength is also almost symmetrical. can do In addition, when heat treatment such as quenching is performed in a later step, warpage can be reduced because the strain distribution is substantially symmetrical in the vertical direction.

(3) In formula (1), V3=0. As a result, processing can be performed using a single-pressing press device in which the die 30 is fixed, and press processing can be performed with simple equipment compared to a double-pressing press device in which both the punch 10 and the die 30 are driven. be able to.

(4) The cylindrical structure 40B manufactured by the manufacturing method V2 under the conditions described in the above formula (1) has the cylindrical portion 41 and the partition plate portion 42 that partitions the inside of the cylindrical portion 41, and The grain flows MF of the shaped structure 40B are formed along the radial direction in the partition plate portion 42, and in the cylindrical portion 41, continue from the partition plate portion 42 and extend from the inner surface to the upper end surface or the lower end surface. , and the direction of the grain flow lines MF on the outer surface is mostly along the radial direction. As a result, the grain flows MF are formed along the shape of the tubular structure 40B without intersecting or discontinuing inside, so that the mechanical properties are better than those manufactured by the conventional method. can be improved.

(5) The cylindrical structure 40B manufactured by the manufacturing method V2 under the above-mentioned formula (1) and the condition of −0.55≦V2/(V1+V3)≦−0.45 is the cylindrical structure 40B. The grain flow lines MF are formed along the radial direction in the partition plate portion 42, and are formed in the cylindrical portion 41 approximately vertically symmetrical about the center plane of the plate thickness of the partition plate portion 42. and As a result, the shape of the tubular structure 40B is substantially symmetrical in the vertical direction, the strain distribution is substantially symmetrical in the vertical direction, and the strength is also considered to be substantially symmetrical in the vertical direction. Machining can be performed with the same cutting load. In addition, when heat treatment such as quenching is performed in a later step, warpage can be reduced because the strain distribution is vertically symmetrical.

An example in which a tubular structure 40B was manufactured by the manufacturing method of the present invention will be described below with reference to FIGS. 9 to 14. FIG.

<Processing conditions>
A cylindrical material 40A of S45C (carbon steel for machine structural use) having a diameter of 24 mm and a plate thickness of 4.2 mm was used as a test material, and a 4000 kN mechanical press (hydraulic unit, Riken Kiki Co., Ltd.) was used as a press device.
The die 30 with a diameter of 17 mm was fixed, the die speed V3 was set to 0 mm/s, the punch speed V1 of the punch 10 with a diameter of 17 mm was set to 10 mm/s, and the container speed V2 of the container 20 with an inner diameter of 24 mm was set to 0 mm/s. It was processed as As a result, a tubular structure with H1 ₀ =3.30 mm and H2 ₀ =4.44 mm was obtained. With H1 ₀ =3.30 mm and H2 ₀ =4.44 mm, the conditional expression (1) for the container speed V2 was obtained. As a result, the conditional expression V2=5×{log(H2/H1)/log(1.35)−1} was obtained. By substituting the desired H2/H1 into this conditional expression of V2, it is possible to obtain a cylindrical structure having the partition plate portion 42 at an arbitrary location.

As Example 1, in order to obtain a cylindrical structure with H2/H1=1, processing was performed under the condition of V2=-5 mm/s. As a result, at V2=-5 mm/s, a cylindrical structure with H1=3.74 mm and H2=3.75 mm was obtained, which was substantially vertically symmetrical.
FIG. 9 shows the results of electroetching the tubular structures obtained under the conditions of V2=0 mm/s and V2=-0.5 mm/s, respectively, cut along the cross section containing the central axis. .

According to FIG. 9, grain flow lines do not intersect in both the tubular structure obtained in the preliminary experiment and the tubular structure of Example 1, and are not interrupted in the middle. It was confirmed that the outer surface was reached. In addition, in Example 1, it was confirmed that the grain flows were substantially symmetrical in the vertical direction with respect to the center line in the plate thickness direction of the partition plate portion.

<Strength test>
Cylindrical structures having partition plates are used in various products after finishing. In the case of the bearing sleeve or the like shown in (b), there are many cases where symmetry is required even in terms of deformation strength. Hereinafter, strength test (1) and strength test (2) were conducted as deformation strength tests to confirm the symmetry.

In order to measure the deformation strength, the test pieces were provided with two types of processing conditions, V2 / V1 = -0.5 and V2 / V1 = 0 (where V3 = 0 mm / s). In order to obtain a vertically symmetrical shape, it was cut to the dimensions shown in FIG. A test piece with V2/V1=−0.5 was taken as Example 2, and a test piece with V2/V1=0 was taken as Reference Example 1.
As the deformation strength test, a strength test (1) shown in FIG. 12(a) and a strength test (2) shown in FIG. 12(b) were performed. In the strength test (1), the test piece prepared with the pressing die 1 and the pressing die 2 is pressed, and the outer peripheral protruding portion of the test piece is pressed downward in the plate thickness direction of the tubular structure using a crushing die. Compression was performed to an amount of 1.2 mm. In the strength test (2), the test piece prepared by the pressing die 1 and the pressing die 2 was pressed, and the outer peripheral protruding part of the test piece was compressed from the radial outside to the inside of the cylindrical structure to a pushing amount of 2.0 mm. did Strength tests (1) and (2) were performed on two types of test pieces on both the upper surface side and the lower surface side from the center line. The results of the strength test (1) are shown in FIG. 13, and the results of the strength test (2) are shown in FIG.

In any test, the test piece of Example 2 showed almost no difference in deformation strength, but the test piece of Reference Example 1 had a difference in deformation strength between the upper surface side and the lower surface side. A large difference occurred in the deformation strength from the lateral surface.
According to the deformation strength test described above, it was found that the deformation strength was also vertically asymmetrical in Reference Example 1, in which the grain flows were vertically asymmetrical. On the other hand, in Example 2, in which the shape is vertically symmetrical and the grain flow lines are substantially vertically symmetrical, it was confirmed that the deformation strength is also vertically symmetrical.

Although the embodiments and examples of the method and apparatus for manufacturing a tubular structure according to the present invention have been described above, the present invention is not limited to the above-described embodiments and examples, and can be modified as appropriate. be.

For example, in the above embodiments and the case where the die speed is set to 0, both the punch and the die may be driven to perform press working.

1 manufacturing device 10 upper die (punch)
20 lateral type (container)
30 lower mold (die)
40A Cylindrical material 40B Cylindrical structure 41 Cylindrical portion 42 Partition plate portion MF Grain flow

Claims (6)

A manufacturing method for manufacturing a cylindrical structure having a cylindrical portion and a partition plate portion for partitioning the interior of the cylindrical portion by front-rear extrusion forging from a cylindrical raw material,
Cylindrical upper and lower dies each having a predetermined diameter smaller than the outer diameter of the cylindrical material inside an annular side mold having an inner diameter at least as large as the outer diameter of the cylindrical material. is installed, and the cylindrical material is arranged between the upper mold and the lower mold,
The speed of the upper mold in the processing direction is set to a predetermined speed V1, the speed of movement of the side mold along the processing direction is set to V2, the speed of the lower mold in the processing direction is set to a predetermined speed V3, and the partition plate portion When the desired length from the thickness center of the cylindrical structure to the upper end of the cylindrical structure is H1 and the desired length to the lower end is H2, the upper mold and the lower mold are relatively close to each other. A manufacturing method in which the side die is moved at a speed of V2 represented by the following formula (1) while pressing the cylindrical material by moving the side die.

However, V1 and V3 are positive in the downward direction, V2 is positive in the upward direction, H10 and H20 are the measured values of H1 and H2 when V2=0, and H1=H2. Except . 2. The manufacturing method according to claim 1, wherein the speed of V2 is set such that -0.55≤V2/(V1+V3)≤-0.45 in the formula (1).
However, when V1=-V3, V2=0. 3. The manufacturing method according to claim 1, wherein V3=0 in said formula (1). A manufacturing apparatus for manufacturing a cylindrical structure having a cylindrical portion and a partition plate portion for partitioning the interior of the cylindrical portion by front-rear extrusion forging from a cylindrical raw material,
a lateral die having an annular shape with an inner diameter at least as large as the outer diameter of the cylindrical material and movable along the processing direction;
a cylindrical upper mold and a lower mold that are installed inside the side mold and have a predetermined diameter smaller than the outer diameter of the cylindrical material;
The speed of the upper mold in the processing direction is set to a predetermined speed V1, the speed of movement of the side mold along the processing direction is set to V2, the speed of the lower mold in the processing direction is set to a predetermined speed V3, and the partition plate portion When the desired length from the thickness center of the cylindrical structure to the upper end of the cylindrical structure is H1 and the desired length to the lower end is H2, the upper mold and the lower mold are relatively close to each other. A manufacturing apparatus that controls the movement of the side die at a speed of V2 represented by the following formula (1).

However, V1 and V3 are positive in the downward direction, V2 is positive in the upward direction, and H10 and H20 are measured values of H1 and H2 when V2=0, respectively , except when H1=H2 . 5. The manufacturing apparatus according to claim 4, wherein the speed of V2 is set such that -0.55≤V2/(V1+V3)≤-0.45 in the formula (1).
However, when V1=-V3, V2=0. 6. The manufacturing apparatus according to claim 4, wherein V3=0 in said formula (1).

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