JPS6040944B2 - Cold forming mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a lining mold, particularly a double or triple cold forming mold.

Fukama forging is a processing method that applies pressure to a metal material with a tool at room temperature or below the recrystallization temperature of the material, and extrudes or fills the metal material along the shape of the tool to create objects of a predetermined shape, improving mechanical properties. However, it has the advantage of being mass-produced with product precision comparable to cutting, but it has greater deformation resistance than hot forging, and there are restrictions on the capacity of processing machines and the strength of mold tools.

Fig. 1 shows the configuration of a forward extrusion cold forming die. Reference numerals 11 and 12 are upper and lower dies, respectively, for metal members made of cemented carbide. The first Akatsuki tai ring 13 made of alloy cold die steel)-61 is made of Akatsuki, and furthermore, SNCM (structural alloy steel) is applied to the outer periphery.
A second dawn pig ring 14 consisting of -8 is baked, and the blank 15 shown in FIG. 2a is made using this cold forming mold.
From this, a front extrusion part 16 as shown in Figure b is obtained.
For large, high-stress molds like this forward extrusion mold, there is a problem that unless double or triple formations are used, the internal pressure will cause the expansion in the downward direction, so double or triple formations are necessary. , while increasing the pressure in the radial direction causes the Akotetsu ring to elongate in the axial direction.

That is, as shown in FIG. 1, since compressive stress 17, 17 acts on the first competition ring 13 from the inside and outside, it expands 18 in the axial direction.
, and the stress caused by heat shrinkage caused by the initial competition is alleviated. Of the Tsuru stress, the axial stress 20 (and A
') becomes particularly small, so if the internal pressure is high, the dividing surface 19 will open, and burrs will enter that area, causing the barrier IJ
If this occurs, the gap will further expand, causing large scratches on the product and making work impossible. Further, Fig. 3 shows the configuration of a compression mold for lining forming, in which 31 is a mold member made of super twill steel, 32 is a mold fixing member made of SKD-11, and 33 is SKD-61. More Daiichi Yakitai Ring, 34
is a second adjacent iron ring made of SNCM-8, and these are assembled by scale iron and press-fitting, and using this lining mold, the blank 35 shown in Fig. 4a is made from the blank 35 shown in Fig. 4b. A compressed part 36 as shown is obtained.

However, in cold forming molds assembled by press-fitting and firing, tensile stress (OBo) during operation
and the competitive compressive stress (bi B') are 37 and 3 in Figure 3.
8, the maximum stress was at the tensile stress Bo during work, and it was impossible to generate the maximum compressive stress at the opening, so the mold was easily damaged and the mold life was short. Ta. The present invention aims to eliminate these problems and provide a cold forming mold that can be processed with high precision and has a long life. In a cold forming mold made of fired iron, a flat inner periphery formed at the outer end of the mold member or cylindrical member, between the mold member and the cylindrical member or between the cylindrical members. A ring-shaped cavity is formed by a notch having a green color and a notch consisting of multiple grooves provided at a position opposite to the notch of the cylindrical member to be cast into the mold member or the cylindrical member. A ring-shaped connecting member is inserted into the mold part, and the mold part and the cylindrical member or the cylindrical members are connected to each other by plastic deformation of the connecting member. The applicant previously press-fitted the same cylindrical member into the outer periphery of the mold member in a single or multiple manner, and when playing drums, used a plastic bonding method to connect the mold member and the cylindrical member or between the cylindrical members. We proposed a cold forming mold made by combining the two.

Here, the plastic bonding method means that the bonded portion of the first bonded member and the second bonded member has a certain height and length, including a recess provided on the surface of the bonded portion of each bonded member. On the other hand, it is made of a material that has lower deformation resistance than the material of both members to be joined and has a predetermined mechanical strength, and has a height and length that is equal to or similar to the height and length of the cavity. Next, this joint village is inserted into the above-mentioned gap, so that the entire A material is substantially surrounded by both the joined part villages and the mold, and the mold This is a method in which the connecting member is pressurized at the convex portion to cause it to flow plastically and flow into the aforementioned recess, and the two members to be connected are bonded by the breaking force and tension force of the connecting member. The present invention makes it possible to further extend the life of this type of mold by improving the shape of the gap in the interline forming mold that is bonded by such a plastic bonding method. Examples will be described below.

FIG. 5 shows an embodiment applied to a front extrusion die, and the same parts as in FIG. 1 are given the same reference numerals.

In this case, the first competition ring is divided into an ascending ring 21 and a lower 1' ring 22, and the descending ring 22 and the second competition ring 14 are plastically connected by a connecting portion 23 made of steel. Fig. 6 shows the formation state of the plastic joint, where 22 is a descending ring, 14 is a second firing ring, and the lower end of the descending ring 22 has a width w of approximately 1.5 to 4 sides. A notch having a flat inner peripheral edge is formed, and the second Akatsuki ring 14 has a double cutout provided over the entire circumference at a position opposite to the notch provided at the outer end of the descending ring 22. A notch consisting of a groove is provided.

In the notch, a ring-shaped peak is formed by forming a double groove. a is 1100. A connecting member with a width smaller than w is inserted into the gap between the descending ring 22 and the second bran ring 14, and a pressurizing convex part of the press mold 24 having a tip surface smaller than the width of the gap is used. The connecting member is pressurized to plastically deform the connecting member and flow into the recessed portions of the descending ring 22 and the second sintering ring 14, thereby forming the connecting portion 23.

At this time, the connecting member, except for the part corresponding to the press die 24,
Since it is surrounded by the descending ring 22 and the second firing ring 14, the coupling member hardly escapes outside the gap when pressurized. Furthermore, if the lengths of the connecting members are made substantially equal to the lengths of the gaps, the connecting portions can be effectively inserted into the recesses. Further, the distance 1 between the end face of the pressing die 24 and the tips of the double grooves of the descending ring 22 and the second firing ring 14 is approximately 0.2 to 2.
Selected as the 5th rib.

If this selection is made, the mold can be easily removed after joining, and the joining member will not flow out in the opposite direction to the insertion direction of the mold, that is, out of the cavity, and the insertion depth will be deep. , it is possible to generate a large internal stress in the connecting member, and therefore a large bonding force can be obtained. Shime allowance is approximately 0.05 feet. Note that there is a relationship between w and 1 as shown in FIG.

In this diagram, the axis is 1 and w is taken as a unit.
The vertical axis shows the torque (k9) and the axial breaking force (k
9) is taken, A is the torque, B is the axial breaking force, and this result is . This shows that the range of ~Reed W is good. Next, details of the groove shape will be described.

FIG. 8 is an enlarged longitudinal sectional view showing an example of the groove portion.

It is assumed that the coupling member constituting the coupling portion 23 flows into the ring-shaped gap from the direction of the arrow. A single peak 142 is formed by the groove 141 of the second baked iron ring 14 . The crest 142 has a triangular cross section and extends over the entire circumference of the groove 141. Note that two or more peaks may be provided, or they may be provided in a spiral shape. FIG. 9 shows an example in which two peaks are provided. The elements that determine the cross-sectional shape of the groove are the depth of the groove, the width B of the groove (upper end), the slope angle Q of the pressure side of the groove, the number of ridges n, the apex angle 0, and the height of the ridge. These practical ranges will be described below.

First, the depth of the groove is 0.1 to 1. The ship's side, preferably 0.
It is best to keep it in the range of 2 to 0.6 skin. If it is too shallow, the side surfaces of the groove will easily undergo plastic deformation when external force is applied in the axial direction, making it impossible to obtain sufficient mechanical strength. If it's too deep,
Insufficient flow of material into the grooves creates voids within the grooves, and as a result, the bonding strength is not increased, and on the contrary, the presence of the voids causes corrosion. Next, the width B of the groove can be changed depending on the cutting strength required for the joining part, but if the width is made too large, the distance from the tip of the upper mold to the bottom of the groove will become longer when joining. , the flow friction loss of the material (coupling member) to be flowed into the premises becomes large.

As a result, even if a large load is applied by the pressing die, the internal stress of the material near the bottom of the groove does not increase enough to cause plastic deformation, and therefore the amount of plastic deformation decreases and the flow of material into the premises is insufficient. Next, the head oblique angle Q of the side surface of the groove 141 on the pressurizing side, that is, the side surface closer to the press die 24 in FIG. 8, has a large effect on the flow of the coupling member into this chamber.

If the oblique angle Q is too large, the gap formed in the groove becomes large and the bonding strength decreases. On the other hand, if the mirror bevel angle Q is too small, the flow of the coupling member into the groove 141 will improve;
The engagement force between the side surface of the joint member 1 and the connecting member is reduced, and the axial breaking force is reduced.

According to experiments, the forehead oblique angle Q is preferably in the range of 20o to 700o, preferably 30o to 60o.

Next, the experimental results for determining the relationship between the number of peaks n and the bonding strength are
Shown in Figure 0. The test materials were two disk-shaped plates made of steel (SS41) and made of steel (OFC-
1/2H) and has a groove with a depth of 0.4 ribs (constant groove width).A coupling ring (combined coupling members). In this figure, both the torque fracture strength shown by C and the cross direction fracture strength shown by D are maximum when the number of ridges n is 2. According to the results of many experiments, it is better to set the number of ridges n to 1 to 3.This means that the number of ridges n in the premise is better than when there are no ridges in the premise, that is, the bottom of the groove is flat. This is because the contact area between the disk-shaped plate and the coupling ring increases, and conversely, the volume of the coupling ring that must be inserted into the groove decreases. This improves the flow of the coupling ring into the premises and increases the degree of adhesion between the coupling ring and each of the disk-like plates, thereby increasing the coupling strength.

As mentioned above, there is a practical range for the groove width B, and if the number n of ridges is increased within this range, the apex angle 8 of the ridges, which will be described later, becomes smaller, which prevents the joining member from flowing into the premises. It becomes insufficient.

The inflow condition deteriorates rapidly as the distance from the pressurizing side, that is, the side close to the press die 24, increases, and almost all of the gaps between the peaks that are away from the pressurizing side remain as voids even after bonding. Figure 11 shows the relationship between the apex angle 8 of the mountain and the bond strength (periodic fracture force) (groove depth H = 0.4 sail, mountain height h =
0.3 side, number of peaks n = 1).

The strength is maximum near the apex angle of 8 = 1100, and in practical terms 8 = 80.
A range of 0 to 1300 is preferable. When the apex angle 8 is small, for example 60o, as shown in Fig. 12, the apex P of the mountain deforms in the direction of the arrow, that is, the direction opposite to the direction of pressure applied by the press die (P'), and a A void g is formed, and a void g is also formed near the bottom of the groove behind the ridge, thus reducing the bonding strength.

Next, there is also a desirable range for the height h of the mountain.

If the height h is too high, the flow resistance when the material enters the groove, particularly to the back surface of the peak, will be large; if it is too small, on the other hand, the purpose of providing the peak will be lost, and it will not contribute to increasing the bonding strength. As mentioned above, there is a certain practical range of the depth of the groove, so the practical range of the mountain height h can be determined in relation to the depth of the groove. FIG. 13 shows an example of the relationship between the ratio of the mountain height h and the groove depth (day) and the bond strength (scale strength against external force in the direction of the vehicle).

Note that the number of peaks n=1, 6=1100, and H=0.4 side. The height of the mountain is 3/2H~day, preferably 1/2H~
7/It is better to make it a known date. An example of the desirable overall shape of the groove determined based on the factors that determine the cross-sectional shape of the groove described above is as follows.

The number of peaks is one (see Figure 8).

Groove width B = 2.0 willow, groove depth H = 0.4 ribs, slope angle of pressure side gutter side Q = 450, mountain height h = 0.3 side, mountain top angle 8 = 110o, Groove bottom width b = 1.2 side. The number of peaks is two (see Figure 9).

B = 2.8 ribs, H Ni〇, 4 ribs, h Ni〇, 3 fences, Q Ni 45
0・h! 〇, 3 ribs, 8=1100, b=2. Enemy cough,
b2 = 1.8 sails. Note that the cross-sectional shape of the mountain does not need to be an equilateral triangle or an isosceles triangle, and in consideration of the flow of the material, the apex angle 8 on the side where the material is pressurized is the apex angle 82 on the far side.
It may be made slightly larger than (8, 182 = a). From a similar point of view, when there are multiple peaks, the height h of the peak closer to the side where the material is pressurized may be made higher than the height h2 of the peak farther away. The cross-sectional shape of the rough peak may be a shape that approximates a triangle, that is, a shape that is approximately triangular but widens toward the bottom, or a trapezoid shape that has a relatively short upper side.

Even in this case, the factors determining the groove shape need to be within the practically possible range as described above. Note that the practical ranges of these elements are valid even if the materials of the coupling member and the materials of the lower ring and the second race ring are changed. That is, in this cold forming mold, after assembling the upper mold member 11, the first dawn ring 21, and the second pseudo bale ring 14, the lower mold member 12 and the lower mold part are assembled. - The Akatsuki ring 22 is finally press-fitted, and the first phosphoric acid ring 22 and the second Keitetsu ring 14 are plastically connected by the connecting portion 23.

This plastic bonding creates the stress OBo (150
The stress on the dividing surface 19 is close to 230k9/ground). ＾″
Yes, the plastic bond is completed in that state, so this c force.
The mold can be assembled while the mold is maintained. Therefore, even if high internal pressure is generated in the mold during work, the dividing surface 19 can be worked without opening, and burrs do not occur, resulting in a long life. A mold was obtained, and it became possible to extend the mold life from the conventional 250 pieces to 190,000 pieces.Also,
As for the upper mold member, the lower mold member is loosely press-fitted, so the competitive effect is increased by about 20% compared to the conventional one, and the molding molding material has sufficient strength in both the collar direction and the ball direction. You can get the mold. In addition, since it is assembled by plastic bonding, there is no need to apply heat.In contrast to conventional methods, where precision was controlled by the dimensional accuracy of the mold members and the first and second Akyo iron rings, plastic bonding is used. In some cases, the dimensional accuracy of each member may be 1/3 to 1/4 of that of the subordinate mold, and the stress can be controlled just by managing the pressure, making mold manufacturing easy. In case of wear, only the lower mold can be replaced by scraping off the plastic joint.

In addition, in this plastic joint, the cutout on the mold member side has a flat inner circumferential green, and the cutout on the cylindrical member side is composed of multiple grooves. Reliability is increased because the amount of plastic deformation that forms the joint part for the inter-forming mold is reduced, and by further providing an annular crest in the groove provided in the part to be joined, The volume of the metal material to be inserted into the groove was reduced, and the contact area at the joint was increased, resulting in less variation and stability, increasing the lifespan by about 60%.

FIG. 14 shows, as another embodiment, an example in which the present invention is applied to a compression mold for cold forming.

The same parts as those in FIG. 34, and the first dawn ring 40 and the second auction ring 34 are plastically connected by a connecting portion 41. Joint part 4
1 is formed in the same manner as in the embodiment of FIG. In a cold forming mold having such a structure, the tensile stress OBo and the baked iron compressive stress H8 during operation are distributed as shown at 37 and 42 in Fig. 14, and OB0≠OB''. I can do it.

That is, a ring-shaped coupling member is inserted between the first Akatsuki tai ring 40 and the second scale ring 34, and the coupling member is pressurized to cause the material to flow into the groove, thereby forming the coupling portion 4.
1 is constructed, and even after the stress is released, the stress that remains inside causes compressive residual stress in the ridge direction, especially in the opening □.

In addition, by adjusting the pressing force p, the value of the compressive stress of the burner can be freely controlled, and the value of the pressing force p can be changed depending on the material actually processed and the processing rate to obtain the optimal compressive stress. can be brought about. Also, blood. Because it is 〒〇B'', there is almost no mold damage, and the conventional mold life is 6
0,000 pieces, it can be extended to 23,000 pieces. In addition, the mold of the compressed part was damaged,
When it wears out, it can be easily disassembled by scraping off the plastic joint, the outer ring can be reused, and the mold can be used in the same way as a new mold by simply remaking the mold for the compressed part. In the above embodiment, an example was shown in which the cylindrical members were connected to each other by a joint portion by a plastic joint, but the same effect can be obtained when the mold member and the cylindrical member are joined by a plastic joint.

As described above, the present invention provides a cold forming mold that can be processed with high precision and has a long life, and has great industrial effects.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a conventional forward extrusion cold forming die, FIGS. 2a and b are perspective views of a blank and a processed product, respectively, during forward extrusion processing, and FIG. FIGS. 4a and 4b are perspective views of a blank and a processed product during compression processing, respectively, and FIG. 5 is a cross-sectional view of a conventional compression mold for cold forming. FIG. 6 is a cross-sectional view of an embodiment in which the mold is applied to a forward extrusion mold, and FIG. 6 is a cross-sectional view showing the process of forming a plastic joint. FIG. 7 is a line diagram explaining the conditions for plastic joint. 9 and 9 are longitudinal cross-sectional views of essential parts of different embodiments of the cold forming mold of the present invention, and FIGS. 10 to 13 show groove shapes and combinations of the cold forming mold of the present invention. FIG. 14, an explanatory diagram showing the relationship with strength, is a sectional view of an embodiment in which the cold forming mold of the present invention is applied to a compression mold. 11, 12...Mold member, 21, 22...
First baked iron ring, 14...Second baked iron ring, 2
3...Connection part, 31...Mold member, 40...
...First competitive IJ ring, 34...Second Akyo iron ring, 41...Connection part. Many figures, many 2 figures, many 3 figures, many 4 figures, many figures, many figures, /2 figures, seven heads, many a figures, many figures, many figures;

Claims (1)

[Scope of Claims] 1. In a cold forming mold in which concentric cylindrical members are press-fitted into the outer periphery of a mold member in a single or multiple manner and are shrink-fitted, the space between the mold member and the cylindrical member or between the cylindrical member and the cylindrical member is A notch having a flat inner peripheral edge formed at an outer end of the mold member or the cylindrical member, and a cylindrical member to be shrink-fitted into the mold member or the cylindrical member between the members. A ring-shaped cavity is formed by a notch formed of multiple grooves provided at a position opposite to the notch, a ring-shaped coupling member is inserted into the cavity, and the plastic deformation of the coupling member causes the above-mentioned A mold for cold forming, characterized in that the mold member and the cylindrical member or the cylindrical members are connected to each other. 2. The mold member is a forward extrusion mold member consisting of an upper mold and a lower mold, and the cylindrical member corresponding to the lower mold and the cylindrical member press-fitted to the outer periphery of the mold member are combined by plastic deformation of a connecting member, and the The cold forming mold according to claim 1, wherein the lower mold is restrained in the axial direction. 3. The cold forming mold according to claim 1, wherein the mold member is a compression mold member, and the mold member is restrained in the compression direction by plastic deformation of a connecting member.