JP4601023B2 - Hollow part forging method and punching pin used therefor - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for forging a hollow part and a punching pin used therefor, and more specifically, for producing a hollow part having a complicated shape, for example, with a difficult-to-process material, The present invention relates to a hollow part forging method capable of simultaneously performing upsetting and the like and a punching pin used for the method.
[0002]
[Prior art]
In a manufacturing method of a brazing ring or the like that uses a material that is relatively easy to process, such as low carbon steel, as shown in FIG. 5, a cylindrical blank 10 is extruded into a cup-shaped member 11. Then, the central surplus portion 11 </ b> A of the cup-shaped member 11 is punched out to form a cylindrical member 12. Then, each process which extrudes to this cylindrical member 12 was implemented in a separate process, and the brazing ring 13 of the target shape was shape | molded.
[0003]
Specifically, in the example shown in FIG. 5, the cylindrical blank 10 is extruded (b) to form a cup-shaped member 11, and then, as shown in FIG. 14. By punching with the punch 15 and the punch pin 16, the central surplus portion 11A of the cup-shaped member 11 is punched to form the cylindrical member 12. Further, as shown in FIG. 6 (b), the cylindrical member 12 is extruded by a cylindrical extrusion process using a die 17, an extrusion punch 18, an inner diameter holding pin (mandrel) 19, and the like. It is a manufacturing method which obtains the brazing ring 13 of a shape.
[0004]
However, in the manufacturing method as shown in FIGS. 5 and 6, the number of forging steps is large and the cost is increased accordingly. Also, because many processes are required, the number of processes that can be used may be insufficient for machines with limited number of processing stages such as homers. Then, it was necessary to process with another equipment such as a cutting machine or to supply the forging machine again. Furthermore, in the processing by the press machine, there is a problem that annealing and lubrication treatment are required between the forging processes, between the punching process and the cylindrical extrusion process, and the cost is increased accordingly.
[0005]
Therefore, in order to reduce the number of processes, as shown in FIG. 7, a forging method is also considered in which, before the punching process, a desired shape is formed without a through hole, and the central surplus portion is punched and completed. It is done. Specifically, in the example shown in FIG. 7, the blank material 21 is formed by a composite extrusion process to form an approximate target shape 22 in a state where the central portions are connected, and then, as shown in FIG. , A punching process with a punch 25 and a punching pin 26, and punching out the central surplus portion 22A of the approximate target shape 22 to obtain a brazed ring 23 having a target shape.
[0006]
[Problems to be solved by the invention]
However, in the manufacturing method as shown in FIG. 7 and FIG. 8, the number of forging processes can be reduced, but the processing itself is difficult, the dimensional accuracy of the product is deteriorated, the mold structure is complicated, the life is short, Various other problems such as unstable conveyance of members between processes occur.
[0007]
Conventionally, difficult-to-process materials such as high carbon chromium bearing steel and martensitic stainless bearing steel are used as the material, and after punching, the inner diameter or outer diameter is ironed with a reduction of about 1% to improve dimensional accuracy. The method was known.
[0008]
However, after punching in FIG. 6 (a), when the brazing ring 13 is formed by performing processing with a larger area reduction as shown in FIG. 6 (b), the workpiece (cylindrical member) 12 In addition to the metal skin without the lubrication film as punched, the inner diameter surface 12A has a high hardness of the material itself, so that the inner diameter holding pin (mandrel) 19 and the cylindrical member 12 are cut off due to the lubricating oil film being cut. Seizure occurs. Therefore, after punching, it is necessary to carry out the forming process of the brazing ring 13 after the lubrication film treatment is performed again on the inner diameter surface 12A of the cylindrical member 12, which increases the cost.
[0009]
[Means for Solving the Problems]
The present invention has been made to solve the above-described conventional problems, and the gist of the present invention is that in the method of manufacturing a hollow part by forging with a difficult-to-process material such as bearing steel as a material, the same processing is performed. In the process, when performing punching processing and extrusion or upsetting of the central surplus portion of the cup-shaped member with a punching pin, a lubricating oil that lubricates the workpiece and the die with a lubrication mechanism incorporated in the forging machine, and Lubricating oil accumulated in the concave portion of the cup-shaped member before punching is discharged from the outer peripheral surface of the tip end portion of the punching pin and used in the forging method for hollow parts and the manufacturing method thereof On the punch pin.
[0010]
As described above, it is possible to reduce the number of processing steps and achieve cost reduction by performing punching processing of the central surplus portion of the cup-shaped member and extrusion or upsetting processing of the cylindrical portion within the same process. In addition, in a forging machine such as Homer, the shortage of the number of processing steps can be solved, and further, the same performance as that of the conventional method can be obtained with respect to the transportability of members between the processes.
[0011]
For difficult-to-work materials such as high carbon chrome bearing steel and martensitic stainless bearing steel, conventional manufacturing is possible by using a punching pin that makes it possible to provide lubricating oil to the inner surface of the workpiece after punching. It is possible to solve various problems such as seizure of the inner diameter surface of the workpiece and the inner diameter holding pin in the cylindrical extrusion process.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail with reference to the embodiment shown in FIG. 1 to FIG. 4. In FIG. 1, first, the same figure (a) comprising difficult-to-work materials such as high carbon chromium bearing steel and martensitic stainless bearing steel. Extrusion processing is performed on the cylindrical blank material 1 shown in FIG. 2 to form a cup-shaped member 2 as shown in FIG. This extrusion process is performed in the same manner as in the prior art.
[0013]
Next, the cup-shaped member 2 after the extrusion process is finished into a target shape in one step by a mold having a structure shown in FIG. In this process, first, the cup-shaped member 2 after the extrusion process is transported from the previous process and inserted into the die 6 by the punching punch 5. When the cup-shaped member 2 is further pushed into the back of the die 6 by the punching punch 5, the punching process of the central surplus portion 2 </ b> A of the cup-shaped member 2 is performed by the punching punch 5 and the punching pin 7. The cylindrical member 3 is formed. The left side of the center line in FIG.
[0014]
Thereafter, the cylindrical member 3 is further pushed into the back of the die 6 by the punching punch 5, and cylindrical extrusion is performed along the inner surface shape of the die 6 and the outer peripheral surface shape of the punching pin 7. A certain brazing ring 4 is formed. The right side of the center line in the figure shows a state where the cylindrical extrusion process is completed and all the processes in this process are completed.
[0015]
After the cylindrical extruding process is completed, the brazed ring 4 waits in a state where it is fitted into the die 6. Then, the stripper 10 that operates in conjunction with the movement of the punching punch 5 starts in the inlet direction of the die 6, and the brazing ring 4 is pushed by the stripper 10 and discharged to the outside of the die 6.
[0016]
Here, the inner surface of the workpiece after punching is normally free of lubricant on the punched surface after punching. In the present invention, the inner surface of the cylindrical member 3 after punching and the punching pin 7 Lubricating with the outer peripheral surface is performed by using the lubricating mechanism incorporated in the forging machine to constantly lubricate the workpiece and the mold and the lubricating oil accumulated in the recess 2B of the cup-shaped member 2 before punching. This is performed by supplying the boundary between the inner diameter surface and the punching pin outer peripheral surface.
[0017]
That is, in the punching pin 7 used in the present invention, as shown in FIGS. 3 and 4, a relief portion 7 </ b> C having a slightly smaller diameter is formed between the punched portion 7 </ b> A and the extruded portion 7 </ b> B. Yes. A vertical through hole 8 is formed in the internal axial direction of the punching pin 7, and a plurality of horizontal holes 9, one of which communicates with the vertical through hole 8 in the internal radial direction of the tip . Then, the other of said lateral hole 9 above is open 9A to the outer peripheral surface of the relief portion 7C of the punching pins 7, the other end of the longitudinal through hole 8 is opened 8A the distal end surface of the punching pins 7.
[0018]
Therefore, in the present invention, as described above, the lubricating oil supplied by the lubrication mechanism incorporated in the forging machine is removed from the other end of the vertical through-hole 8 when the central surplus portion 2A of the cup-shaped member 2 is punched. From the opening 8A on the tip end surface of the punching pin 7 , one of them flows into a radial lateral hole 9 communicating with the longitudinal through hole 8, and the punching from the opening 9A formed on the outer peripheral surface of the relief portion 7C of the lateral hole 9 The pin 7 is discharged toward the outer peripheral surface of the tip.
[0019]
At the same time, the lubricating oil in the recess 2B of the cup-shaped member 2 before punching passes from the opening 8A opening in the front end surface of the vertical through hole 8 through the horizontal hole 9 to the outer peripheral surface of the escape portion 7C. It is discharged from the opening 9 </ b> A that is open toward the outer peripheral surface side of the tip of the punching pin 7. Therefore, the lubricating oil is supplied again to the boundary between the inner diameter surface of the cylindrical member 3 and the outer peripheral surface of the punching pin 7, and lubrication between the inner diameter surface of the cylindrical member 3 and the pushing portion 7 </ b> B of the punching pin 7 is performed. Can be secured.
[0020]
Here, the amount of lubricating oil flowing into the gap between the inner diameter surface of the cylindrical member 3 and the relief portion 7C of the punching pin 7 is the hole diameter φd2 of the vertical through hole 8 formed in the punching pin 7, and the vertical through hole. This is made possible by adjusting the hole diameter φd1 of the opening 8A that opens to the tip end surface side of the pin 8 and the hole diameter φd3 of the opening 9A that opens to the outer peripheral surface of the relief portion 7C of the lateral hole 9.
[0021]
That is, if the hole diameter φd2 of the vertical through hole 8 is made smaller than the hole diameter φd1 of the opening 8A and the hole diameter φd3 of the opening 9A is made equal to the hole diameter φd1 of the opening 8A, Lubricating oil flow increases. At least φd3 must satisfy the relationship φd1> φd2 = φd3.
[0022]
In addition, as a prior art of the punching pin, there is one described in Japanese Utility Model Publication No. 5-19143. This punching pin (punching punch) discharges the lubricating oil in the recess 2B of the cup-shaped member 2 to the outside. It is aimed at. Accordingly, the punching pin disclosed in the Japanese Utility Model Publication No. 5-19143 is insufficient to provide for the purpose of preventing seizure occurrence in the above-described processing and improving the lubricity on the work inner diameter surface. The great effect of improving the lubricity of the punching pin cannot be expected.
[0023]
【The invention's effect】
Since the present invention is configured as described above, the number of processing steps can be reduced, and the manufacturing cost can be reduced. In addition, with the conventional method, due to restrictions on the number of machining steps of the machine, it is possible to produce hollow parts that require post-processing such as cutting and resupply to the forging machine with only one supply to the forging machine. If it can be done, the performance equivalent to the conventional method can be obtained also about the conveyance property of the member between each process.
[0024]
In addition, especially in forging of hollow parts using difficult-to-process materials such as bearing steel, annealing and lubrication can be omitted, and the number of processing steps can be reduced, resulting in a significant reduction in manufacturing costs. There are various effects such as.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a processing step of a processing method of the present invention.
FIG. 2 is an explanatory view showing the punching process of FIG. 1 and the subsequent extrusion process.
FIG. 3 is a front view of a punching pin according to the present invention and a right side view of the same drawing.
FIG. 4 is an enlarged cross-sectional view of a tip portion of the punching pin.
FIG. 5 is an explanatory diagram of processing steps of a conventional processing method.
FIG. 6 is an explanatory view showing a punching process (a) and a cylindrical extrusion process (b), respectively.
FIG. 7 is an explanatory diagram of processing steps of another conventional processing method.
FIG. 8 is an explanatory view showing a punching process.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Blank material 2 Cup-shaped member 2A Center surplus part 2B Recessed part 3 Cylindrical member 4 Ring with flange 7 Punching pin 7A Punching part 7B Extrusion part 7C Escape part 8 Vertical through-hole 8A Same opening 9 Lateral hole 9A Same opening

Claims (5)

In the method of manufacturing a hollow part by forging a difficult-to-process material such as bearing steel as a raw material, when performing punching processing and extrusion or upsetting of the central surplus portion of the cup-shaped member with a punching pin within the same processing process, Lubricating oil that lubricates the workpiece and mold with a lubrication mechanism incorporated in the forging machine, and lubricating oil accumulated in the concave portion of the cup-shaped member before punching from the outer peripheral surface of the tip of the punching pin A method for forging a hollow part, wherein the forging is performed after discharging.   The method for forging a hollow part according to claim 1, wherein a reduction in area of the extrusion or upsetting is 5% or more. The internal axial direction has a vertical through-hole, and one or more lateral holes extending in the internal radial direction are formed in which one communicates with the vertical through-hole and the other opens on the outer peripheral surface of the tip. A punching pin used in the method for forging a hollow part according to 1 or 2 .   4. The punching pin used in the method for forging a hollow part according to claim 3, wherein the opening of the horizontal hole is formed on the outer peripheral surface of the relief part between the punching part and the extrusion part and having a slightly smaller diameter. . The dimensions of the hole diameter φd2 of the vertical through hole, the hole diameter φd1 of the opening formed in the tip end surface of the vertical through hole, and the hole diameter φd3 of the outer hole of the escape portion of the horizontal hole are at least φd1 The punching pin used in the method for forging a hollow part according to claim 3 or 4, wherein a relationship of> φd2 = φd3 is satisfied.

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