JP7437214B2 - Forming method for caulking parts - Google Patents

Description

The present invention relates to a method for forming a caulking member.

In the case of members such as pistons, an attempt has been made to increase the strength of an aluminum alloy material by forging and caulking an iron-based ring reinforcing material around the material (Patent Document 1). In the forging process using caulking as described above, it is required to plastically deform a cylindrical material such as a piston to join the iron-based ring without any gaps.

To perform such plastic deformation, it is necessary, for example, to press the upper and lower surfaces of the cylindrical material synchronously with upper and lower punches. Such synchronous pressing is required to be performed using, for example, a press device that is equipped with a lower die that causes a sub-cylinder that is activated by the lowering of the upper punch and upper die that make up the upper mold to raise the piston of the main cylinder. (Patent Document 2).

Special Publication No. 51-21946 Special Publication No. 55-46255

However, in the method described in Patent Document 2, in order to join the iron ring to the cylindrical material without any gaps, the speed difference between the upper and lower punches that press the upper and lower surfaces of the cylindrical material is appropriately set, and the It is necessary to deform the material along the shape of the iron ring at the same time.

However, in the method described in Patent Document 2, the lower punch is driven by the sub-cylinder activated by the lowering of the upper die by raising the piston of the main cylinder, so in order to change the speed of the lower punch, it is necessary to Since it is necessary to change the area of the piston inside, there is a problem in that the speed difference between the upper and lower punches cannot be easily controlled. Another problem is that such double-acting presses are expensive.

On the other hand, when caulking is attempted with a single-action press, fluctuations in the material flow of the cylindrical material occur, making it impossible to join the cylindrical material and the iron-based ring without any gaps.

The present invention provides a method of firmly caulking a ring-shaped material to a bulk material to form a caulking member even when an inexpensive single-action press device is used.

The present invention is as shown below.
(1) A method of caulking a ring-shaped material onto a cylindrical material to form a caulking member, the press device having a lower die and an upper die, and driving the lower die and the upper die in a direction of approaching and separating them. and a step of placing a cylindrical material having a large diameter portion, a small diameter portion, and a tapered portion that connects one end side of the large diameter portion and one end side of the small diameter portion in the lower mold. , a step of fitting the inner circumferential surface of the cylindrical part of the ring-shaped guide member having the cylindrical part to the large diameter part of the cylindrical material; A ring-shaped material having a ring-shaped flange protruding in a radially inward direction of the cylindrical material is arranged such that the inner circumferential surface of the cylindrical portion engages with the outer circumferential surface of the cylindrical portion of the ring-shaped guide member, and the flange a step of arranging the cylindrical material and the ring-shaped material so as to contact with the small-diameter portion of the cylindrical material, and driving the press device to press the cylindrical material and the ring-shaped material onto the upper surface of the cylindrical material through the ring-shaped guide member. a step of forging by crimping the mold and the lower mold;
A method for forming a caulking member, the method comprising:
(2) The ring-shaped guide member has a flange projecting radially outward from the cylindrical part, and the axial cross section of the cylindrical material has an L-shape. (1) The method for forming a caulking member described in .
(3) A method for forming a piston preform by caulking a ring member on the outer circumferential surface of the piston, the method comprising a lower mold and an upper mold, and driving the lower mold and the upper mold in directions toward and away from each other. a step of preparing a press device; and a step of placing a piston material in the lower die, which includes a large diameter portion, a small diameter portion, and a tapered portion that connects one end side of the large diameter portion and one end side of the small diameter portion. and a step of fitting the inner circumferential surface of the cylindrical portion of the ring-shaped guide member having the cylindrical portion to the large diameter portion of the piston material; A ring-shaped material having a ring-shaped flange protruding in a radially inward direction of the piston material is arranged such that the inner circumferential surface of the cylindrical portion engages with the outer circumferential surface of the cylindrical portion of the ring-shaped guide member, and the flange portion a step of arranging the piston material so as to be in contact with the small diameter portion of the piston material, and driving the press device to press the piston material and the ring material into contact with the upper die and the ring material through the ring-shaped guide member. A method for forming a piston preform, the method comprising the step of forging by caulking with a lower die.
(4) According to (3), the ring-shaped guide member has a flange portion projecting radially outward from the cylindrical portion, and an axial cross section of the piston material has an L-shape. A method for forming the piston preform as described.
(5) The method includes the steps of removing the cylindrical portion of the ring-shaped guide member and the cylindrical portion of the ring-shaped material, and forming a groove in the flange of the ring-shaped material. The method for forming a piston preform according to (3) or (4).

According to the present invention, a cylindrical material having a large diameter part, a small diameter part, and a tapered part that connects one end side of the large diameter part and one end side of the small diameter part is placed in a lower mold, and then the cylindrical part A ring-shaped guide member having a ring-shaped guide member is fitted into a large diameter portion of a cylindrical material, and a cylindrical portion and a ring-shaped flange portion protruding from a substantially central portion of the cylindrical portion in a radially inward direction of the cylindrical material. A ring-shaped material having a ring-shaped material is disposed such that the inner circumferential surface of the cylindrical portion engages with the outer circumferential surface of the cylindrical portion of the ring-shaped guide member, and the collar portion abuts against the small diameter portion of the cylindrical material. .

Therefore, when the above-mentioned cylindrical material is pressed with, for example, an upper mold, the height of the cylindrical material decreases, and the area where the flange of the ring-shaped material comes into contact also descends, so that the plasticity of the cylindrical material around the flange decreases. There will be sufficient flow. Note that the lowering of the above portion is ensured by a groove formed between the lower part of the cylindrical portion of the ring-shaped material and the ring-shaped guide member.

On the other hand, in the ring-shaped material, the inner circumferential surface of the cylindrical portion engages with the outer circumferential surface of the cylindrical portion of the ring-shaped guide member, and the cylindrical portion of the ring-shaped material is disposed between the small diameter portion of the cylindrical material and the upper die. exists. Therefore, the material of the cylindrical material that has plastically flowed does not go around to the rear beyond the cylindrical portion of the ring-shaped material. As a result, only the collar portion of the ring-shaped material is caulked to the cylindrical material.

As a result, the present invention provides a method for firmly caulking the flange of a ring-shaped material corresponding to a ring material onto a cylindrical material to form a caulking member even when an inexpensive single-action press device is used. be able to.

FIG. 3 is a schematic diagram showing steps of a method for forming a caulking member according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing steps of a method for forming a caulking member according to an embodiment of the present invention. It is a schematic diagram showing a forging process in a method of forming a caulking member according to an embodiment of the present invention. It is a schematic diagram showing a forging process in a method of forming a caulking member according to an embodiment of the present invention. It is a schematic diagram showing a forging process in a method of forming a caulking member according to an embodiment of the present invention. It is a schematic diagram showing a forging process in a method of forming a caulking member according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing steps of a method for forming a caulking member according to an embodiment of the present invention.

Hereinafter, a method for forming a caulking member according to an embodiment of the present invention will be described. 1, 2, and 7 are schematic diagrams showing steps of a method for forming a caulking member according to an embodiment of the present invention. FIG. 2 is an enlarged view of a portion surrounded by a broken line in FIG. 1, that is, a portion where a ring-shaped guide member and a ring-shaped material are provided. 3 to 6 are schematic diagrams showing a forging process in a method for forming a caulking member according to an embodiment of the present invention.

First, as shown in FIG. 1, a press device having an upper die 15 consisting of an upper die 11 and an upper punch 12 and a lower die 19 consisting of a lower die 16 and a lower punch 17 is prepared. The upper mold 15 and the lower mold 19 are driven in the direction of approaching and separating. In addition, in FIG. 1, description of a press machine and the like is omitted in order to simplify and explain the method of forming a caulking member in this embodiment.

Next, as also shown in FIG. 1, the bulk material 21 is placed in the lower mold 19. The bulk material 21 includes a large-diameter first cylindrical portion 211, a small-diameter second cylindrical portion 212, and an intermediate portion having a tapered outer circumferential surface that connects one end side of the first cylindrical portion 211 and one end side of the second cylindrical portion 212. It has a section 213.

In addition, when forming a piston preform as a caulking member, an aluminum alloy material, for example, can be used as the bulk material 21.

Next, as shown in FIGS. 1 and 2, the ring-shaped guide member 31 is fitted into the first cylindrical portion 211 of the bulk material 21. The ring-shaped guide member 31 has a cylindrical portion 311 and a flange portion 312 that protrudes radially outward from the cylindrical portion 311, and has a cross section perpendicular to the axial direction of the bulk material 21, that is, the upper mold 15 and the lower mold 19. It has an L-shape. In this case, the inner peripheral surface of the cylindrical portion 311 of the ring-shaped guide member 31 is made to fit into the first cylindrical portion 211 of the bulk material 21 . In addition, the edge part of the upper end part of the cylindrical part 311 is chamfered, and the edge part of the tip part of the collar part 312 is also chamfered.

In addition, by fitting the inner circumferential surface of the cylindrical portion 311 of the ring-shaped guide member 31 to the first cylindrical portion 211 of the bulk material 21, the cylindrical portion 311 of the ring-shaped guide member 31 and the intermediate portion 213 of the bulk material 21 are connected. A first gap S1 is formed between them.

The ring-shaped guide member 31 can be made of any material, but for example, it can be made of a steel-based material that does not adhere to the bulk material 21. Additionally, ceramic materials can also be used.

Next, as shown in FIGS. 1 and 2, the small-diameter second cylindrical portion 212 of the bulk material 21 is provided with a cylindrical portion 411 and a cylindrical portion protruding from approximately the center of the cylindrical portion 411 in the radially inward direction of the bulk material 21. A ring-shaped material 41 having a ring-shaped flange 412 is provided. At this time, the inner circumferential surface of the cylindrical portion 411 engages with the outer circumferential surface of the cylindrical portion 311 of the ring-shaped guide member 31, and the flange portion 412 forms the boundary between the small-diameter second cylindrical portion 212 and the intermediate portion 213 of the bulk material 21. so that it is in contact with the Note that the upper and lower edges of the cylindrical portion 411 are each chamfered, and the edge of the tip that abuts the boundary of the flange 412 is also chamfered.

At this time, a second gap S2 and a third gap S3 are formed between the cylindrical part 411 of the ring-shaped material 41 and the second cylindrical part 212 and intermediate part 213 of the bulk material 21.

By engaging the inner circumferential surface of the cylindrical portion 411 of the ring-shaped material 41 with the outer circumferential surface of the cylindrical portion 311 of the ring-shaped guide member 31, a fourth A gap S4 is formed.

The ring-shaped material 41 forms a piston preform as a caulking member, and when an aluminum alloy material is used as the bulk material 21, an iron-based material, specifically stainless steel, case hardened steel, and maraging material is used as a reinforcing material. Steel etc. can be used.

Next, the press device is driven to lower the upper die 15, for example. Then, as shown in FIG. 3, the bulk material 21 is pressed, and the upper material expands toward the second gap S2, plastically flows, and begins to wrap around the flange 412 of the ring-shaped material 41. At this time, since a fourth gap S4 is formed between the lower end of the cylindrical part 411 of the ring-shaped material 41 and the flange part 312 of the ring-shaped guide member 31, as the bulk material 21 is pressed down, the ring-shaped material 41 also descends (slides downward) through the fourth gap S4.

As the pressing further progresses, as shown in FIG. 4, the plastic flow of the bulk material 21 progresses and the material on the lower side also expands toward the first gap S1 and the third gap S3, causing the flange 412 of the ring-shaped material 41 to expand. Start wrapping. At this time, the ring-shaped member 41 further descends, but this descent is ensured by the fourth gap S4.

As the pressing further progresses, as shown in FIG. 412 will become more inclusive. Then, as the pressing progresses further, as shown in FIG. 6, the material of the bulk material 21 fills the mold, fills the first gap S1, second gap S2, and third gap S3, and fills the ring-shaped material 41. The flange portion 412 is completely caulked into the bulk material 21 to complete the forging.

At this time, as described above, the outer circumferential surface of the cylindrical portion 311 of the ring-shaped guide member 31 and the inner circumferential surface of the cylindrical portion 411 of the ring-shaped material 41 are engaged, and the ring-shaped guide member 31 is positioned below the ring-shaped material 41. Therefore, it is possible to avoid the bulk material 21 from wrapping around behind the ring-shaped material 41 from the lower part of the cylindrical portion 411 of the ring-shaped material 41 due to plastic flow. Furthermore, a cylindrical portion 411 of the ring-shaped material 41 is present between the small-diameter second cylindrical portion 212 of the bulk material 21 and the upper mold 15 . Therefore, the material of the bulk material 21 that has undergone plastic flow does not go around the cylindrical portion 411 of the ring-shaped material 41 to the rear.

As a result, only the ring-shaped collar portion 412 of the ring-shaped material 41 is caulked to the bulk material 21 and forged.

Note that when the caulking member obtained through the above steps is used as the piston preform 50, for example, as shown in FIG. 7, the ring-shaped guide member 31 and the ring-shaped material exposed on the surface of the caulking member After removing the cylindrical portion 411 of 41, a groove 51 is formed in the flange portion 412 caulked into the bulk material 21.

As described above, according to the present embodiment, even if an inexpensive single-action press device is used, the flange portion 412 of the ring-shaped material 41 corresponding to the ring material is firmly swaged to the bulk material 21, and a swaged member is formed. can be provided.

Although several embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and changes can be made without departing from the gist of the invention. These embodiments and their modifications are included within the scope and gist of the invention, as well as within the scope of the invention described in the claims and its equivalents.

For example, in the embodiment described above, the ring-shaped guide member 31 has the flange portion 312 that protrudes radially outward from the cylindrical portion 311, but the flange portion 312 can be omitted. Even in such a case, the inner circumferential surface of the cylindrical portion 411 of the ring-shaped material 41 engages with the outer circumferential surface of the cylindrical portion 311 of the ring-shaped guide member 31 on the lower end side of the cylindrical portion 411. A fourth gap S4 is formed. Therefore, as the bulk material 21 is pressed down, the ring-shaped material 41 can also be moved down via the fourth gap S4. However, the fourth gap S4 can be more stably formed when the flange 312 is provided.

Further, since the outer circumferential surface of the cylindrical portion 311 of the ring-shaped guide member 31 and the inner circumferential surface of the cylindrical portion 411 of the ring-shaped material 41 are engaged, and the cylindrical portion 311 extends downward, the bulk material 21 It is possible to avoid the ring-shaped material 41 from moving backward from the lower part of the cylindrical portion 411 of the ring-shaped material 41 due to plastic flow.

11 Upper die 12 Upper punch 15 Upper die 16 Lower die 17 Lower punch 19 Lower die 21 Bulk material 211 Large diameter first cylindrical part 212 (of bulk material) Small diameter second cylindrical part 213 (of bulk material) ) Ring-shaped guide member 311 Cylindrical portion 312 (of the ring-shaped guide member) Flange portion 41 (of the ring-shaped guide member) Ring-shaped material 411 Cylindrical portion 412 (of the ring-shaped material) Flange (of ring-shaped member)

Claims (5)

A method of caulking a ring-shaped material to a cylindrical material to form a caulking member,
preparing a press device having a lower die and an upper die and driving the lower die and the upper die in a direction toward and away from each other;
placing in the lower mold a cylindrical material having a large diameter part, a small diameter part, and a tapered part that connects one end side of the large diameter part and one end side of the small diameter part;
a step of fitting an inner circumferential surface of a ring-shaped guide member having a cylindrical portion into a large diameter portion of the cylindrical material;
A ring-shaped material having a cylindrical portion and a ring-shaped flange protruding in a radially inward direction of the cylindrical material from a substantially central portion of the cylindrical portion is provided such that the inner circumferential surface of the cylindrical portion is shaped like the ring. engaging with the outer circumferential surface of the cylindrical portion of the guide member and disposing the flange portion in contact with the small diameter portion of the cylindrical material;
driving the press device and forging the cylindrical material and the ring material by crimping them with the upper die and the lower die via the ring-shaped guide member;
A method for forming a caulking member, the method comprising: The ring-shaped guide member has a flange portion projecting radially outward from the cylindrical portion, and the axial cross section of the cylindrical material has an L-shape. Method of forming caulking parts. A method of forming a piston preform by caulking a ring member on the outer peripheral surface of the piston, the method comprising:
preparing a press device having a lower die and an upper die and driving the lower die and the upper die in a direction toward and away from each other;
placing a piston material in the lower mold, which includes a large diameter portion, a small diameter portion, and a tapered portion that connects one end side of the large diameter portion and one end side of the small diameter portion;
a step of fitting an inner circumferential surface of a ring-shaped guide member having a cylindrical portion into a large diameter portion of the piston material;
A ring-shaped material having a cylindrical part and a ring-shaped flange protruding from a substantially central part of the cylindrical part in a radially inward direction of the piston material, the inner peripheral surface of the cylindrical part is connected to the ring-shaped guide. engaging with the outer circumferential surface of the cylindrical portion of the member and disposing the flange portion in contact with the small diameter portion of the piston material;
driving the press device and forging the piston material and the ring-shaped material by crimping them with the upper die and the lower die via the ring-shaped guide member;
A method for forming a piston preform, the method comprising: The piston according to claim 3, wherein the ring-shaped guide member has a flange projecting radially outward from the cylindrical portion, and an axial cross section of the piston material has an L-shape. Method of forming a preform. removing the cylindrical portion of the ring-shaped guide member and the cylindrical portion of the ring-shaped material;
forming a groove in the flange of the ring-shaped material;
The method for molding a piston preform according to claim 3 or 4, comprising:

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