JP7167820B2 - Manufacturing method of circular material - Google Patents

Description

FIELD OF THE DISCLOSURE The present disclosure relates to a method for manufacturing circular members.

Circular materials such as railway wheels, gears, rings, etc. are manufactured, for example, as follows. First, the billet is heated. One or more forgings are performed on the heated billet to form a preform. The preformed material is subjected to finish rolling, finish forging, and the like to form the preformed material into a predetermined outer shape and dimensions. Thereafter, heat treatment, machining, etc. are performed as necessary to obtain a circular material.

For example, Patent Literature 1 discloses a method of manufacturing a circular member that is a scroll component of an air conditioner compressor. In this method, a preformed material is formed by upsetting an aluminum alloy round bar, and this preformed material is forged using a punch and a die. The preformed material is forced by a punch into a die space for forming the vanes of the scroll component. Back pressure in the direction opposite to the growth direction is applied to the blade portion while the blade portion is growing in the preformed material.

WO 01/77398

By the way, as one type of circular member, one having a thin curved disc portion and a thick outer peripheral portion is known. Such a circular member is formed by bending a preformed member using a mold consisting of an upper mold and a lower mold. Specifically, a flat disc portion of the preform is supported by a lower die, and the preform is pressed down by an upper die to bend the disc portion.

However, when the disc portion is bent, the material near the outer periphery of the preform flows radially outward and downward. Therefore, the outer peripheral portion tends to separate radially outward from the lower mold, and the outer peripheral portion tends to be underfilled.

An object of the present disclosure is to provide a method for manufacturing a circular material that can suppress underfill.

A method for manufacturing a circular member according to the present disclosure includes a preparation process and a forging process. In the preparation step, a preform is prepared that includes a disk portion and an outer peripheral portion that is connected to the outer peripheral edge of the disk portion and is thicker than the disk portion. In the forging process, the preformed material is forged with a die including an upper die and first and second lower dies. The forging process includes a restraining process and a bending process. In the constraining step, the disk portion is placed on the first lower mold, and the upper mold is lowered with the outer peripheral portion facing the second lower mold, and the outer peripheral portion is sandwiched between the second lower mold and the upper mold. . In the bending step, after the restraining step, the upper die is further lowered to reach the bottom dead center, and the disk portion of the preform is bent by the upper die and the first lower die.

According to the method for manufacturing a circular member according to the present disclosure, underfill can be suppressed.

FIG. 1 is a vertical cross-sectional view of a circular member manufactured by a manufacturing method according to an embodiment. FIG. 2 is a vertical cross-sectional view of a preform that is a raw material for the circular member shown in FIG. FIG. 3 is a 1/2 vertical sectional view of a die used in the forging process of the manufacturing method according to the embodiment. FIG. 4 is a schematic diagram for explaining the forging process. FIG. 5 is a schematic diagram for explaining the forging process. FIG. 6 is a schematic diagram for explaining the forging process. FIG. 7 is a schematic diagram for explaining the forging process. FIG. 8 is a schematic diagram for explaining a forging step of a manufacturing method according to another embodiment. FIG. 9 is a schematic diagram for explaining a case of manufacturing a circular material by a general method.

A method for manufacturing a circular member according to an embodiment includes a preparation step and a forging step. In the preparation step, a preform is prepared that includes a disk portion and an outer peripheral portion that is connected to the outer peripheral edge of the disk portion and is thicker than the disk portion. In the forging process, the preformed material is forged with a die including an upper die and first and second lower dies. The forging process includes a restraining process and a bending process. In the constraining step, the disk portion is placed on the first lower mold, and the upper mold is lowered with the outer peripheral portion facing the second lower mold, and the outer peripheral portion is sandwiched between the second lower mold and the upper mold. . In the bending step, after the restraining step, the upper die is further lowered to reach the bottom dead center, and the disk portion of the preform is bent by the upper die and the first lower die (first configuration).

In the method for manufacturing a circular member according to the first configuration, while the disk portion of the preformed member is bent by the upper die and the first lower die, the outer peripheral portion of the preformed member is sandwiched between the upper die and the second lower die. are constrained by As a result, the radially outward flow of the material is restricted during the forging of the preformed material, and the outer peripheral portion can be made to conform to the first lower die. Therefore, the lack of thickness in the outer peripheral portion can be suppressed.

In the above method for manufacturing a circular member, the mold may further include an elastic member that biases the second lower mold upward (second configuration).

According to the second configuration, due to the action of the elastic member, the second lower die presses the outer peripheral portion from below, so that the outer peripheral portion can be more firmly restrained by the upper die and the second lower die. Therefore, the material becomes more difficult to flow, and the lack of thickness in the outer peripheral portion can be further suppressed.

In the first configuration, the mold may further include a driving device for vertically moving the second lower mold (third configuration).

According to the third configuration, by controlling the driving device to move the second lower mold up and down, it is possible to arbitrarily set the force and timing with which the outer peripheral portion is restrained by the upper mold and the second lower mold.

Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. The same reference numerals are given to the same or corresponding parts in the drawings, and the description thereof will not be repeated.

[Configuration of circular material]
First, a circular member 1 manufactured by the manufacturing method according to the present embodiment will be described with reference to FIG. FIG. 1 is a longitudinal sectional view of a circular member 1. FIG. A vertical section refers to a section cut along a plane including the central axis A1 of the circular member 1 . In the circular member 1, the direction in which the central axis A1 extends is the axial direction or the thickness direction, and the direction perpendicular to the central axis A1 is the radial direction.

As shown in FIG. 1 , the circular member 1 includes a curved disc portion 11 and an outer peripheral portion 12 .

When viewed in the axial direction of the circular member 1, the outer shape of the curved disc portion 11 is substantially circular. The curved disk portion 11 may be in the shape of an annular disk, or may be in the shape of a disk without holes. In this embodiment, the curved disk portion 11 is a disk-like shape without holes. In a vertical cross-sectional view of the circular member 1, the curved disc portion 11 has a curved shape. Specifically, the central portion in the radial direction of the curved disk portion 11 protrudes toward one side in the axial direction.

In this embodiment, the curved disc portion 11 has a substantially constant thickness over its entirety. However, the curved disc portion 11 may have a portion that is thicker than other portions. For example, when the curved disc portion 11 is in the shape of an annular disc, the inner peripheral portion of the curved disc portion 11 can be made thicker than the other portions.

The outer peripheral portion 12 surrounds the curved disc portion 11 . The outer peripheral portion 12 is connected to the outer peripheral edge 111 of the curved disc portion 11 . The outer peripheral portion 12 is thicker than the curved disc portion 11 . The thickness of the outer peripheral portion 12 is at least greater than the thickness of the outer peripheral edge 111 of the curved disk portion 11 . Therefore, in the circular member 1 , the outer peripheral portion 12 protrudes from the outer peripheral edge 111 of the curved disk portion 11 to both sides in the thickness direction.

[Manufacturing method of circular material]
Next, a method for manufacturing the circular member 1 will be described. The manufacturing method of the circular member 1 according to this embodiment includes a preparation process and a forging process.

(Preparation process)
With reference to FIG. 2, in the preparation step, a preformed material 2 as a material for circular material 1 (FIG. 1) is prepared. FIG. 2 is a longitudinal sectional view of the preform 2. As shown in FIG. The vertical section here refers to a section cut along a plane including the central axis A2 of the preform 2 . In the preformed material 2, the direction in which the central axis A2 extends is the axial direction or the thickness direction, and the direction perpendicular to the central axis A2 is the radial direction.

The preformed material 2 can be obtained, for example, by forging a steel billet one or more times. The preformed material 2 includes a disc portion 21 and an outer peripheral portion 22 .

The disc portion 21 is a portion corresponding to the curved disc portion 11 ( FIG. 1 ) of the circular member 1 , and, like the curved disc portion 11 , has a substantially circular outer shape when viewed in the axial direction of the preformed member 2 . have. However, the disc portion 21 is not curved and is generally flat.

The thickness of the disc portion 21 is generally constant throughout, corresponding to the curved disc portion 11 (FIG. 1) of the circular member 1 . When the curved disc portion 11 of the circular member 1 has a thick inner peripheral portion, the inner peripheral portion of the disc portion 21 of the preformed member 2 is also thicker than the other portions of the disc portion 21 .

The disc portion 21 has an outer peripheral edge 211 . The outer peripheral portion 22 is connected to the outer peripheral edge 211 . The outer peripheral portion 22 surrounds the disk portion 21 . The outer peripheral portion 22 is a portion corresponding to the outer peripheral portion 12 ( FIG. 1 ) of the circular member 1 .

The outer peripheral portion 22 is thicker than the disc portion 21 . The outer peripheral portion 22 protrudes from the disk portion 21 to one side and the other side in the thickness direction in a vertical cross-sectional view of the preform member 2 . That is, the preform 2 has a substantially H-shaped longitudinal section.

(Forging process)
In the forging process, the prepared preformed material 2 is forged.

A die 3 shown in FIG. 3 is used in the forging process. FIG. 3 shows a 1/2 vertical sectional view of the mold 3. FIG. First, the mold 3 will be explained.

Referring to FIG. 3, mold 3 is attached to a known press (not shown). The mold 3 includes an upper mold 31 , a first lower mold 32 and a second lower mold 33 . Mold 3 further includes an elastic member 34 .

The upper die 31 is attached to a ram of a press (not shown) and is vertically movable. The upper die 31 presses down the preformed material 2 from above. A convex portion 311 and a flat portion 312 are provided on the lower surface of the upper mold 31 . The convex portion 311 protrudes downward from the flat portion 312 . The convex portion 311 has a shape corresponding to the curved disk portion 11 ( FIG. 1 ) of the circular member 1 . That is, the convex portion 311 has a curved shape corresponding to one surface of the curved disk portion 11 in the axial direction. The flat portion 312 is provided around the convex portion 311 . The flat portion 312 is connected to the outer peripheral edge of the convex portion 311 . The flat portion 312 extends substantially horizontally from the outer peripheral edge of the convex portion 311 .

The first lower mold 32 includes a body portion 321 and a flange portion 322 . An upper surface 321 a of the body portion 321 faces the convex portion 311 of the upper mold 31 . The upper surface 321 a is a processing surface for forming the curved disc portion 11 ( FIG. 1 ) of the circular member 1 together with the convex portion 311 of the upper mold 31 , and has a shape corresponding to the curved disc portion 11 . That is, the upper surface 321a has a curved shape corresponding to the other surface of the curved disk portion 11 in the axial direction.

The flange portion 322 is provided around the body portion 321 . The flange portion 322 protrudes from the body portion 321 to the outer peripheral side thereof. The flange portion 322 is connected to the lower portion of the body portion 321 .

The second lower mold 33 is provided around the body portion 321 of the first lower mold 32 and faces the flat portion 312 of the upper mold 31 . The second lower mold 33 is positioned above the flange portion 322 of the first lower mold 32 . The second lower mold 33 is supported by the flange portion 322 via the elastic member 34 .

A lower end portion of the elastic member 34 is connected to the flange portion 322 of the first lower mold 32 . An upper end portion of the elastic member 34 is connected to the second lower mold 33 . The elastic member 34 biases the second lower mold 33 upward. The biasing force of the elastic member 34 is set to be weaker than the pressing force of the upper die 31 . The elastic member 34 is, for example, a spring or a hydraulic damper.

Next, the process of forging the preformed material 2 with the die 3 will be described with reference to FIGS. 4 to 7. FIG. 4 to 7 are schematic diagrams for explaining the forging process of the preformed material 2. FIG. The forging process includes a restraining process of restraining the outer peripheral portion 22 of the preformed material 2 and a bending process of bending the disc portion 21 of the preformed material 2 .

Referring to FIG. 4 , in the restraining step, first, disk portion 21 of preform 2 is placed on first lower mold 32 . More specifically, the central portion of the disc portion 21 is placed on the body portion 321 of the first lower mold 32 . At this time, the outer peripheral portion of the disc portion 21 does not come into contact with the upper surface 321a of the body portion 321 . In addition, the outer peripheral portion 22 of the preformed material 2 faces the second lower mold 33 without contacting it.

When the upper die 31 is lowered from this state, the projections 311 come into contact with the preformed material 2 as shown in FIG. More specifically, the protruding portion 311 contacts the outer peripheral portion of the disk portion 21 of the preform 2 that is not in contact with the first lower mold 32 from above. As a result, the outer peripheral portion of the disk portion 21 moves downward, and the outer peripheral portion 22 also moves downward. That is, the disc portion 21 and the outer peripheral portion 22 are pushed down by the upper die 31 .

The outer peripheral portion 22 of the preformed material 2 comes into contact with the second lower mold 33 when it descends by a predetermined distance. Since the second lower mold 33 is urged upward by the elastic member 34, after the outer peripheral part 22 reaches the second lower mold 33, the lowering speed of the outer peripheral part 22 decreases. While the lowering of the outer peripheral portion 22 is prevented by the second lower mold 33, the upper mold 31 continues to descend without slowing down. As a result, as shown in FIG. 6 , the flat portion 312 of the upper mold 31 contacts the outer peripheral portion 22 and the outer peripheral portion 22 is sandwiched between the second lower mold 33 and the flat portion 312 . This completes the restraining process.

After completion of the restraining process, a bending process is performed. In the bending step, the upper die 31 is further lowered to bend the disc portion 21 . At this time, the outer peripheral portion 22 is sandwiched and restrained between the second lower mold 33 and the upper mold 31 . In this state, as shown in FIG. 7, when the upper die 31 is lowered to reach the bottom dead center, the outer peripheral portion of the disc portion 21 contacts the main body portion 321 of the first lower die 32, and the upper die 31 and the first lower mold 32 form the disk portion 21 into a desired curved shape. Thereby, as shown in FIG. 7, the bending process is completed and the circular material 1 is obtained.

[effect]
When manufacturing the circular material 1 by a general method, for example, as shown in FIG. Apply. At this time, since the bending of the disk portion 21 is started before the outer peripheral portion 22 reaches the lower mold 92, the material of the outer peripheral portion 22 flows radially outward and downward of the preformed material 2. . Therefore, the inner diameter of the outer peripheral portion 22 is enlarged, and a gap S is generated between the outer peripheral portion 22 and the lower die 92 in the radial direction. As a result, the outer peripheral portion 12 of the manufactured circular member 1 tends to be underfilled. In contrast, in the method of manufacturing the circular member 1 of the present embodiment, the disc portion 21 is bent while the outer peripheral portion 22 is constrained by the upper mold 31 and the second lower mold 33 . Therefore, the radially outward flow of the material is suppressed, and a gap is less likely to occur between the outer peripheral portion 22 and the first lower mold 32 in the radial direction. Therefore, it is possible to suppress the lack of thickness in the outer peripheral portion 12 of the manufactured circular member 1 .

When there is a possibility that the outer peripheral portion 12 of the circular member 1 may be insufficiently thick, generally, the outer peripheral portion 22 of the preformed member 2, which is the raw material, is provided with excess thickness to compensate for the insufficient thickness. There is a need. Therefore, the weight of the material put into the preformed material 2 increases, and the yield decreases. Moreover, in the circular member 1 manufactured from the preformed member 2, the excess material to be removed by machining or the like increases, so the processing load increases. Furthermore, when the disk portion 21 of the preformed material 2 is pressed down by the die 9, the outer peripheral portion 22 is pushed out radially outward, so the outer peripheral portion 22 needs to have excess thickness radially inward or in the thickness direction. If the outer peripheral portion 22 of the preformed material 2 has excess thickness on the inner side in the radial direction, the outer peripheral portion 22 may rub against the mold 9 during processing, and the circular material 1 may be damaged. Even if the outer peripheral portion 22 has extra thickness in the thickness direction, the outer peripheral portion 22 may buckle when the upper die 31 reaches the bottom dead center, and the circular material 1 may be damaged.

On the other hand, in the method for manufacturing the circular member 1 of the present embodiment, the outer peripheral portion 12 of the circular member 1 is suppressed from being underfilled, so it is unnecessary to provide excess thickness to the outer peripheral portion 22 of the preformed member 2. do not have. Therefore, it is possible to reduce the weight of the material put into the preformed material 2 and improve the yield. In addition, since machining or the like for removing excess material from the circular member 1 can be eliminated or minimized, the processing load can be reduced. Furthermore, scratches on the circular member 1 caused by excess thickness of the preformed member 2 can be suppressed.

In the method of manufacturing the circular member 1 of this embodiment, the elastic member 34 urges the second lower mold 33 upward. Therefore, the outer peripheral portion 22 can be firmly sandwiched between the second lower mold 33 and the upper mold 31, and the flow of the material during the bending of the disc portion 21 is further suppressed. Therefore, the lack of thickness in the outer peripheral portion 22 can be further suppressed.

Further, when the convex portion 311 of the upper die 31 presses down the disk portion 21, the lower surface of the outer peripheral portion 22 tends to warp toward the outer peripheral side. By urging the second lower mold 33 upward by the elastic member 34 , the normal force that the outer peripheral portion 22 receives from the second lower mold 33 increases, and the force between the lower surface of the outer peripheral portion 22 and the second lower mold 33 increases. Friction increases. This frictional force prevents the lower surface of the outer peripheral portion 22 from warping outward. Therefore, it becomes difficult for the inner diameter of the outer peripheral portion 22 to expand, and the lack of thickness in the outer peripheral portion 22 can be further suppressed.

The method for manufacturing the circular member according to the present embodiment has been described above. In addition, the present disclosure is not limited to the above embodiments, and it goes without saying that various modifications are possible without departing from the scope of the present disclosure.

For example, in the embodiment described above, the second lower mold 33 contacts the outer peripheral portion 22 of the preform 2 before the upper mold 31 in the restraining step. However, the upper die 31 may contact the outer peripheral portion 22 before the second lower die 33 . In short, it is sufficient that the outer peripheral portion 22 is sandwiched between the upper die 31 and the second lower die 33 before the upper die 31 reaches the bottom dead center. does not matter.

In the above embodiment, the case where the mold 3 includes the elastic member 34 has been described. However, the mold 3 may include a driving device 35 instead of the elastic member 34, as shown in FIG. The upper end of the driving device 35 is connected to the second lower mold 33 . A lower end portion of the driving device 35 may be connected to the flange portion 322 of the first lower mold 32 or may be connected to a bolster plate (not shown). The driving device 35 is configured to be extendable and retractable by hydraulic control. The drive device 35 is, for example, a hydraulic cylinder.

With the mold 3 having such a configuration, the driving device 35 can freely move the second lower mold 33 in the vertical direction. Therefore, the force for restraining the outer peripheral portion 22 by the upper die 31 and the second lower die 33 can be arbitrarily set during forging, and the second lower die 33 can be applied to the outer peripheral portion of the preformed material 2 at an arbitrary timing. 22 can be contacted.

For example, by placing the preform 2 on the first lower mold 32 and extending the driving device 35 , the second lower mold 33 can be brought into contact with the outer peripheral portion 22 before the upper mold 31 . Alternatively, the driving device 35 may be controlled to extend so that the second lower mold 33 contacts the outer peripheral portion 22 at the same time as the upper mold 31 . Further, as in the above embodiment, the drive device 35 can be controlled to extend so that the second lower mold 33 comes into contact with the outer peripheral portion 22 after the upper mold 31 does. After the second lower mold 33 contacts the outer peripheral portion 22, the driving device 35 is retracted according to the lowering speed of the upper mold 31 while the outer peripheral portion 22 is constrained by the second lower mold 33 and the upper mold 31. while the upper die 31 reaches the bottom dead center. Thereby, the disc portion 21 of the preform 2 can be bent by the upper mold 31 and the first lower mold 32 .

In the manufacturing method according to the above embodiment, the circular material obtained in the forging process may be a finish forged product or a rough forged product. If the circular material is a rough forged material, this circular material becomes the final product through finish forging, machining, and the like.

The forging process for forming the circular material may be performed hot or cold. When the forging process is performed hot, the preformed material may be heated to a predetermined temperature before the forging process.

1: Circular Material 11: Curved Disk Part 111: Peripheral Edge 12: Peripheral Part 2: Preformed Material 21: Disk Part 211: Peripheral Edge of Disk Part 22: Peripheral Part 3: Mold 31: Upper Mold 32: First lower mold 33: Second lower mold 34: Elastic member 35: Driving device

Claims (3)

A method for manufacturing a circular member, comprising:
a disk portion;
A preparation step of preparing a preformed material including an outer peripheral portion connected to the outer peripheral edge of the disc portion and having a thickness greater than that of the disc portion;
a forging step of forging the preformed material with a mold including an upper mold and first and second lower molds,
The forging process includes
The disk portion is placed on the first lower mold, and the upper mold is lowered while the outer peripheral portion is opposed to the second lower mold, and the outer peripheral portion is separated from the second lower mold and the upper mold. a restraining step of sandwiching between molds;
a bending step of further lowering the upper die to reach a bottom dead center after the restraining step, and bending the disc portion of the preformed member by the upper die and the first lower die. manufacturing method. A method for manufacturing a circular member according to claim 1,
The mold further includes:
A method for manufacturing a circular member, including an elastic member that biases the second lower mold upward. A method for manufacturing a circular member according to claim 1,
The mold further includes:
A method for manufacturing a circular workpiece, including a driving device for vertically moving the second lower mold.

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