JPH03140B2 - - Google Patents

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Application Field) The present invention relates to a method for manufacturing a rotationally symmetric hollow article that is suitable for manufacturing a rotationally symmetric hollow article having a continuous central opening extending in the axial direction and a circumferential groove on the outer surface. (Prior Art) A rotationally symmetrical hollow product having a continuous central opening extending in the axial direction and a circumferential groove on the outer surface, for example, a continuous central opening 50a extending in the axial direction and a circumferential groove 50f on the outer surface having a shape as shown in FIG. Rotationally symmetric hollow article 50 having
In the past, everything was done through cutting. (Problems to be Solved by the Invention) However, when forming the continuous central opening 50a extending in the axial direction, the circumferential groove 50f on the outer surface, etc. by cutting, the processing time is long, which reduces productivity. There were problems such as low material yield and poor working environment due to the generation of cutting waste. (Purpose of the Invention) This invention was made by focusing on these conventional problems, and it has an extremely short machining time and excellent productivity, and since it does not involve cutting, the material yield is extremely good. It is an object of the present invention to provide a method for manufacturing a rotationally symmetric hollow product that does not cause deterioration of the working environment due to the generation of cutting debris.

[Structure of the invention]

(Means for Solving the Problems) As a means for solving the above problems, a method for manufacturing a rotationally symmetric hollow article according to the present invention has a continuous central opening extending in the axial direction, and a circumferential groove on the outer surface. 1) Enlarging the outer diameter of a solid cylindrical metal material to a required diameter, and then drilling a first blind hole extending in the axial direction in one end face of the same material to a predetermined axial depth. 2) Drilling a second blind hole extending in the axial direction to a predetermined axial depth on the end surface opposite to the hole-drilled part of the blank in the previous step, forming a double-blind hole; 3) A step of forming a blind hole at a depth such that the axial position of the same part approximately corresponds to the axial position of the circumferential groove, leaving a partition part in between; By applying pressure in the direction, the diameter of the outer periphery on the side where the first blind hole is formed and the outer periphery on the side where the second blind hole is formed are gradually increased in diameter as they approach the smaller diameter side, while leaving the portion of the outer surface corresponding to the circumferential groove with a small diameter. 4) punching out the partition portion between the first blind hole and the second blind hole in the axial direction to form a conical surface and a cylindrical surface at the same time; This method aims to achieve the intended purpose by employing a means of manufacturing a rotationally symmetrical hollow product from a solid cylindrical metal material by forming a continuous central opening through which a second blind hole passes. . (Embodiment) FIGS. 1 to 6 show an embodiment of the present invention, and FIGS. 1 to 5 show the main parts of a mold used in each process. 1A and 1B show the preliminary process, 11 is a front punch, and 12 is a sleeve disposed concentrically on the outer circumferential side of the front punch 11. FIG. Further, 14 is a rear punch, and 15 is a correction space forming surface 15a that is arranged concentrically on the outer peripheral side of the rear punch 14 and forms a correction space 16 with the rear punch 14, and has a through hole in the rear punch 14. 15b. 2a and 2b show the first step, 21 is a front punch, and 22 is a sleeve disposed concentrically on the outer circumferential side of the front punch 21. FIG. Further, 24 is a rear punch, 27 is a material support sleeve provided concentrically on the outer circumferential side of the rear punch 24, and 25 is a rear punch 24.
and a die having a molding space forming surface 25a which is arranged concentrically on the outer peripheral side of the material supporting sleeve 27 and forms an annular molding space 26 with the rear punch 24. 3a and 3b show the second step, 31 is a front punch, 32 is a sleeve arranged concentrically on the outer periphery of the front punch 31, and 33 is a sleeve 33 arranged on the outer periphery of the front punch 31 at one end of the sleeve 32. These are material pressers arranged concentrically. Also, 34 is a backward punch,
37 is a material support sleeve provided concentrically on the outer circumferential side of the rear punch 34, and 35 is a material support sleeve provided concentrically on the outer circumferential side of the rear punch 34 and the material support sleeve 37 and between it and the front punch 31 after forward movement. This die has a molding space forming surface 35a that can form an annular molding space 36. 4a and 4b show the third step, 41 is a front punch, 42 is arranged concentrically on the outer circumferential side of the front punch 41, and has a small inner diameter surface 42a for restraining the material, a conical inclined surface 42b, and the front punch. The sleeve has a large inner diameter surface 42c for forming a molding space 46a between the molding space 41 and the molding space 41. Further, 44 is a rear punch, and 45 is arranged concentrically on the outer peripheral side of the rear punch 44, and forms a forming space 46b between the small inner diameter surface 45a for material restraint, the conical inclined surface 45b, and the rear punch 44. This sleeve has a large inner diameter surface 45c for forming a molding space. 5a and 5b show the fourth step, 51 is a front punch, 52 is a sleeve arranged concentrically on the outer periphery of the front punch 51, and 53 is a sleeve 53 arranged on the outer periphery of the front punch 51 at one end of the sleeve 52. This is a hollow product presser arranged concentrically. Further, 57 is a material supporting sleeve having a discharge hole 54 for discharging the cut piece 50c cut by the front punch 51;
A die 55 is arranged concentrically on the outer peripheral side of the material supporting sleeve 57 and has a material restraining surface 55a. Next, a procedure for manufacturing a rotationally symmetrical hollow article 50 having a continuous central opening 50a extending in the axial direction and a circumferential groove 50f on the outer surface as shown in FIG. 6 will be described. In the preliminary steps shown in FIGS. 1a and 1b, as shown in FIG. The front punch 11 and the sleeve 12 are inserted into the space 16, as shown in FIG. 1b.
By moving the front punch 11 and the rear punch 14, the cylindrical metal material 1 shown in FIG. The straightening material 10 is enlarged in diameter to a required diameter, and then the front punch 11 and sleeve 12 are retreated, and the rear punch 14 is advanced to take out the correction material 10. Next, in the first step shown in FIGS. 2a and 2b, as shown in FIG.
By moving the front punch 21 and sleeve 22 as shown in FIG. A first blind hole 20a extending in the axial direction is punched to a predetermined depth in the axial direction in the half-finished product 20, and then the front punch 21 and sleeve 22 are retreated, and the tip of the material supporting sleeve 27 is cut with a die. 25
By advancing it to the outside of the blank 20
Take out. Next, in the second step shown in FIGS. 3a and 3b, as shown in FIG. From the side, the molding space 36 in the die 35
the first blind hole 20a and the rear punch 34.
By fitting the front punch 31, sleeve 32 and material presser 33 as shown in FIG. 3b, the blank 20 shown in FIG. 3a is produced.
By performing backward extrusion from one end surface side of the material, a second blind hole 30b is formed in the center of the material, leaving a partition portion 30c between the first blind holes 30a and (20a) that have already been formed. It is assumed that the semi-finished product is 30. At this time, the first blind hole 30a and the second blind hole 30b
By setting the axial depth of the first
The axial position of the partition portion 30c formed between the blind hole 30a and the second blind hole 30b corresponds to the circumferential groove 50f.
so that it approximately corresponds to the axial position of. Next, after retracting the front punch 31 and extracting the front punch 31 from the first blind hole 30b,
The blank 30 is taken out from the die 35 by retracting the sleeve 32 and the material presser 33 and advancing the tip of the material supporting sleeve 37 to the outside of the die 35 . Next, in the third step shown in FIGS. 4a and 4b, as shown in FIG. 4a, the blank 30 obtained in the second step is charged into the die 45 and
The blind hole 30a and the rear punch 44 are fitted to restrain the surface of the first blind hole 30a, and the outer circumferential surface of the material forming the first blind hole 30a is fitted to the material restraining small inner diameter surface 45a. to place the part in a restrained state. Next, as shown in FIG. 4a, the front punch 41 is moved to the second position.
By fitting into the blind hole 30b, the second blind hole 3
0b is restrained, and the sleeve 42 is moved to fit the outer circumferential surface of the material forming the second blind hole 30b into the material restraining small inner diameter surface 42a, thereby bringing the relevant portion into a restrained state. Then, by further moving the sleeve 42, the sleeve 42 and the die 45 press both end surfaces of the blank product 30. During this pressurization, as described above, both tip portions of the blank product 30 are located between the small inner diameter surface 42a for material restraint formed on the sleeve 42 and the front punch 41, and between the material restraining surface 42a formed on the die 45. Although each is restrained between the small inner diameter surface 45a and the rear punch 44,
A conical inclined surface 42b continuous with the small inner diameter surface 42a for restraining the material and a large inner diameter surface 42 for forming a molding space.
There is an annular molding space 4 between c and the front punch 41.
6a is formed, and a conical inclined surface 45a continuous to the small inner diameter surface 45a for restraining the material, a large inner diameter surface 45c for forming a forming space, and the rear punch 4.
An annular molding space 46b is also formed between the first blind hole 30a and the second blind hole 30.
Since the partition portion 30c remains between the sleeve 42 and the fourth
As shown in FIG. b, a conical inclined surface 42 is formed on the sleeve 42 and the die 45 from the constrained tip portion to the unconstrained portion.
The partition portion 30c corresponding to the axial position of the circumferential groove 51f is not susceptible to plastic deformation and is therefore left with a small diameter to form the first blind hole 30a. and the outer circumferential side having the second blind hole 30b are respectively enlarged in the radial direction so as to approach the small diameter portion, so that a conical surface and a cylindrical surface are formed at the same time, and as a result, the partition portion 40c (30c) Grooved semi-finished product 40 with a circumferential groove 40f formed on the corresponding outer periphery
becomes. After forming this grooved semi-finished product 40, only the front punch 41 is retreated to extract it from the deformed second blind hole 40b, then the sleeve 42 is retreated, and the rear punch 44 is further moved to form the grooved semi-finished product. Item 4
Extract 0. Next, in the fourth step shown in FIGS. 5a and 5b, the grooved blank 40 obtained in the third step is placed on the material restraining surface 55 of the die 55, as shown in FIG. 5a.
After charging into the hole 40a, as shown in FIG. 50c is cut off and discharged into the discharge hole 54, thereby forming a continuous central opening 50a at the center of the grooved blank 40 shown in FIG. 5a, as shown in FIG. 5b. Thus, by going through the first to fourth steps described above, a rotationally symmetrical hollow article 50 having a continuous central opening 50a in the center portion and a circumferential groove 50f on the outer surface as shown in FIG. 6 is obtained. . In the above explanation, the process of forming the rotationally symmetrical hollow product 50 from the cylindrical metal material 1 through each process was shown in order, but in reality each process is performed simultaneously and in parallel, and the preliminary process is In the fourth step, while the front punch 11 makes one reciprocation to straighten the cylindrical metal material 1, the front punch 51 makes one reciprocation in the fourth step.
By reciprocating and forming a continuous central opening 50a, a rotationally symmetrical hollow article 50 is obtained.

【Effect of the invention】

In the method for manufacturing a rotationally symmetrical hollow article according to the present invention, the outer diameter of a solid cylindrical metal material is expanded to a required diameter, and then a first blind hole extending in the axial direction is inserted into one end surface of the material. A second blind hole extending in the axial direction is punched to a predetermined axial depth on the end surface opposite to the holed part of the blank in the previous step, and a double blind hole is formed. A process of leaving a partition part in between and making the blind hole depth such that the axial position of the part almost corresponds to the axial position of the circumferential groove, and adding an axial direction to both end faces of the blank from the previous process By applying pressure, the outer periphery on the side where the first blind hole is formed and the outer periphery on the side where the second blind hole is formed are sequentially radially moved closer to the smaller diameter side, leaving the portion of the outer surface corresponding to the circumferential groove with a small diameter. expanding to simultaneously form a conical surface and a cylindrical surface, and punching out the partition portion between the first blind hole and the second blind hole in the axial direction to form the first blind hole and the second blind hole. Since rotationally symmetrical hollow products are manufactured from a solid cylindrical metal material through the process of forming a continuous central opening through which the cylindrical hole is formed, the machining time when manufacturing rotationally symmetrical hollow products is reduced by cutting. It is possible to significantly shorten the time compared to the previous one, and it is possible to significantly improve productivity. Furthermore, since no cutting is involved, the material yield is extremely good, and there is a significant effect in that the deterioration of the working environment due to the generation of cutting waste can be eliminated.

[Brief explanation of the drawing]

Figures 1 to 5 show an embodiment of the present invention at each step, and a in each figure is a longitudinal cross-sectional view of the mold and material in the state before molding, and b in each figure is a longitudinal cross-sectional view of the mold and the material in the state after molding. FIG. 6 is a longitudinal sectional view of the mold and the material, and FIG. 6 is a front view showing one form of a rotationally symmetrical hollow product. 1, 10... Cylindrical metal material, 11, 21, 3
1, 41, 51...forward punch, 12, 22, 3
2, 42, 52...Sleeve, 14, 24, 3
4, 44...Backward punch, 15, 25, 35, 4
5, 55... Dice, 20, 30, 40... Semi-finished product, 20a, 30a, 40a... First blind hole, 3
0b, 40b...Second blind hole, 30c, 40c...
Partition part, 50...Rotationally symmetrical hollow product, 50a...
...Continuous central opening, 50f...Peripheral groove, 57...Sleeve.

Claims (1)

[Claims] 1. A method for manufacturing a rotationally symmetrical hollow article having a continuous central opening extending in the axial direction and having a circumferential groove on the outer surface, comprising: 1) enlarging the outer diameter of a solid cylindrical metal material to a required diameter; , then drilling a first blind hole extending in the axial direction in one end surface of the same material by stamping to a predetermined axial depth; A second blind hole extending in the direction is punched to a predetermined axial depth, leaving a partition portion between the two blind holes, and the axial position of the portion approximately corresponds to the axial position of the circumferential groove. 3) Forming a first blind hole by applying pressure in the axial direction to both end surfaces of the blank from the previous step, leaving a portion of the outer surface corresponding to the circumferential groove with a small diameter. 4) forming a conical surface and a cylindrical surface at the same time by sequentially expanding the outer periphery of the side and the outer periphery of the second blind hole forming side in the radial direction as they approach the small diameter side; and punching out the partition part between the blind holes in the axial direction to form a continuous central opening through which the first blind hole and the second blind hole pass through, thereby rotating a solid cylindrical metal material. A method for manufacturing a rotationally symmetrical hollow product, the method comprising manufacturing a symmetrical hollow product.